Better error handling + other changes

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/Char.java

@@ -5,18 +5,19 @@
  * reference the LICENSE file in this module's root directory.
  */
 
-package com.dfsek.terra.addons.terrascript.tokenizer;
+package com.dfsek.terra.addons.terrascript.lexer;
+
+import java.util.Objects;
+
 
 public class Char {
     private final char character;
-    private final int index;
-    private final int line;
+    private final SourcePosition position;
     
     
-    public Char(char character, int index, int line) {
+    public Char(char character, SourcePosition position) {
         this.character = character;
-        this.index = index;
-        this.line = line;
+        this.position = position;
     }
     
     public boolean is(char... tests) {
@@ -33,18 +34,23 @@ public class Char {
         return Character.toString(character);
     }
     
+    @Override
+    public boolean equals(Object o) {
+        if(this == o) return true;
+        if(o == null || getClass() != o.getClass()) return false;
+        Char other = (Char) o;
+        return character == other.character && Objects.equals(position, other.position);
+    }
+    
+    @Override
+    public int hashCode() {
+        return Objects.hash(character, position);
+    }
+    
     public char getCharacter() {
         return character;
     }
     
-    public int getIndex() {
-        return index;
-    }
-    
-    public int getLine() {
-        return line;
-    }
-    
     public boolean isWhitespace() {
         return Character.isWhitespace(character);
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/Lexer.java

@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2020-2021 Polyhedral Development
+ *
+ * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in this module's root directory.
+ */
+
+package com.dfsek.terra.addons.terrascript.lexer;
+
+import com.google.common.collect.Sets;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.Stack;
+
+import com.dfsek.terra.addons.terrascript.lexer.Token.TokenType;
+import com.dfsek.terra.addons.terrascript.lexer.exceptions.EOFException;
+import com.dfsek.terra.addons.terrascript.lexer.exceptions.FormatException;
+import com.dfsek.terra.addons.terrascript.lexer.exceptions.TokenizerException;
+import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
+
+
+public class Lexer {
+    public static final Set<Character> syntaxSignificant = Sets.newHashSet(';', '(', ')', '"', ',', '\\', '=', '{', '}', '+', '-', '*', '/',
+                                                                           '>', '<', '!'); // Reserved chars
+    private final LookaheadStream reader;
+    private final Stack<Token> bracketStack = new Stack<>();
+    private Token current;
+    
+    public Lexer(String data) {
+        reader = new LookaheadStream(data + '\0');
+        current = tokenize();
+    }
+    
+    /**
+     * Get the first token.
+     *
+     * @return First token
+     *
+     * @throws ParseException If token does not exist
+     */
+    public Token current() {
+        return current;
+    }
+    
+    /**
+     * Consume (get and remove) the first token.
+     *
+     * @return First token
+     *
+     * @throws ParseException If token does not exist
+     */
+    public Token consume(String wrongTypeMessage, TokenType expected, TokenType... more) {
+        if(!current.isType(expected) && Arrays.stream(more).noneMatch(t -> t == current.getType())) throw new ParseException(wrongTypeMessage, current.getPosition());
+        return consumeUnchecked();
+    }
+    
+    public Token consumeUnchecked() {
+        if(current.getType() == TokenType.END_OF_FILE) return current;
+        Token temp = current;
+        current = tokenize();
+        return temp;
+    }
+    
+    /**
+     * Whether this {@code Tokenizer} contains additional tokens.
+     *
+     * @return {@code true} if more tokens are present, otherwise {@code false}
+     */
+    public boolean hasNext() {
+        return current.getType() != TokenType.END_OF_FILE;
+    }
+    
+    private Token tokenize() throws TokenizerException {
+        consumeWhitespace();
+        SourcePosition position = reader.getPosition();
+        
+        // Skip line if comment
+        while(reader.matchesString("//", true)) skipLine();
+        
+        // Skip multi line comment
+        if(reader.matchesString("/*", true)) skipTo("*/");
+        
+        // Reached end of file
+        if(reader.current().isEOF()) {
+            if(!bracketStack.isEmpty()) throw new ParseException("Dangling open brace", bracketStack.peek().getPosition());
+            return new Token(reader.consume().toString(), TokenType.END_OF_FILE, position);
+        }
+        
+        // Check if operator token
+        if(reader.matchesString("==", true))
+            return new Token("==", TokenType.EQUALS_EQUALS, position);
+        if(reader.matchesString("!=", true))
+            return new Token("!=", TokenType.BANG_EQUALS, position);
+        if(reader.matchesString(">=", true))
+            return new Token(">=", TokenType.GREATER_EQUAL, position);
+        if(reader.matchesString("<=", true))
+            return new Token("<=", TokenType.LESS_EQUALS, position);
+        if(reader.matchesString(">", true))
+            return new Token(">", TokenType.GREATER, position);
+        if(reader.matchesString("<", true))
+            return new Token("<", TokenType.LESS, position);
+        
+        // Check if logical operator
+        if(reader.matchesString("||", true))
+            return new Token("||", TokenType.BOOLEAN_OR, position);
+        if(reader.matchesString("&&", true))
+            return new Token("&&", TokenType.BOOLEAN_AND, position);
+        
+        // Check if number
+        if(isNumberStart()) {
+            StringBuilder num = new StringBuilder();
+            while(!reader.current().isEOF() && isNumberLike()) {
+                num.append(reader.consume().getCharacter());
+            }
+            return new Token(num.toString(), TokenType.NUMBER, position);
+        }
+        
+        // Check if string literal
+        if(reader.current().is('"')) {
+            reader.consume(); // Consume first quote
+            StringBuilder string = new StringBuilder();
+            boolean ignoreNext = false;
+            while((!reader.current().is('"')) || ignoreNext) {
+                if(reader.current().is('\\') && !ignoreNext) {
+                    ignoreNext = true;
+                    reader.consume();
+                    continue;
+                } else ignoreNext = false;
+                if(reader.current().isEOF())
+                    throw new FormatException("No end of string literal found. ", position);
+                string.append(reader.consume());
+            }
+            reader.consume(); // Consume last quote
+            
+            return new Token(string.toString(), TokenType.STRING, position);
+        }
+        
+        if(reader.current().is('('))
+            return new Token(reader.consume().toString(), TokenType.OPEN_PAREN, position);
+        if(reader.current().is(')'))
+            return new Token(reader.consume().toString(), TokenType.CLOSE_PAREN, position);
+        if(reader.current().is(';'))
+            return new Token(reader.consume().toString(), TokenType.STATEMENT_END, position);
+        if(reader.current().is(','))
+            return new Token(reader.consume().toString(), TokenType.SEPARATOR, position);
+        
+        if(reader.current().is('{')) {
+            Token token = new Token(reader.consume().toString(), TokenType.BLOCK_BEGIN, position);
+            bracketStack.push(token);
+            return token;
+        }
+        if(reader.current().is('}')) {
+            if(bracketStack.isEmpty()) throw new ParseException("Dangling close brace", position);
+            bracketStack.pop();
+            return new Token(reader.consume().toString(), TokenType.BLOCK_END, position);
+        }
+        
+        if(reader.current().is('='))
+            return new Token(reader.consume().toString(), TokenType.ASSIGNMENT, position);
+        if(reader.current().is('+'))
+            return new Token(reader.consume().toString(), TokenType.PLUS, position);
+        if(reader.current().is('-'))
+            return new Token(reader.consume().toString(), TokenType.MINUS,
+                             position);
+        if(reader.current().is('*'))
+            return new Token(reader.consume().toString(), TokenType.STAR,
+                             position);
+        if(reader.current().is('/'))
+            return new Token(reader.consume().toString(), TokenType.FORWARD_SLASH, position);
+        if(reader.current().is('%'))
+            return new Token(reader.consume().toString(), TokenType.MODULO_OPERATOR, position);
+        if(reader.current().is('!'))
+            return new Token(reader.consume().toString(), TokenType.BANG, position);
+        
+        // Read word
+        StringBuilder token = new StringBuilder();
+        while(!reader.current().isEOF() && !isSyntaxSignificant(reader.current().getCharacter())) {
+            Char c = reader.consume();
+            if(c.isWhitespace()) break;
+            token.append(c.getCharacter());
+        }
+        String tokenString = token.toString();
+        
+        // Check if word is a keyword
+        if(tokenString.equals("true"))
+            return new Token(tokenString, TokenType.BOOLEAN, position);
+        if(tokenString.equals("false"))
+            return new Token(tokenString, TokenType.BOOLEAN, position);
+        
+        if(tokenString.equals("num"))
+            return new Token(tokenString, TokenType.TYPE_NUMBER, position);
+        if(tokenString.equals("str"))
+            return new Token(tokenString, TokenType.TYPE_STRING, position);
+        if(tokenString.equals("bool"))
+            return new Token(tokenString, TokenType.TYPE_BOOLEAN, position);
+        if(tokenString.equals("void"))
+            return new Token(tokenString, TokenType.TYPE_VOID, position);
+        
+        if(tokenString.equals("if"))
+            return new Token(tokenString, TokenType.IF_STATEMENT, position);
+        if(tokenString.equals("else"))
+            return new Token(tokenString, TokenType.ELSE, position);
+        if(tokenString.equals("while"))
+            return new Token(tokenString, TokenType.WHILE_LOOP, position);
+        if(tokenString.equals("for"))
+            return new Token(tokenString, TokenType.FOR_LOOP, position);
+        
+        if(tokenString.equals("return"))
+            return new Token(tokenString, TokenType.RETURN, position);
+        if(tokenString.equals("continue"))
+            return new Token(tokenString, TokenType.CONTINUE, position);
+        if(tokenString.equals("break"))
+            return new Token(tokenString, TokenType.BREAK, position);
+        if(tokenString.equals("fail"))
+            return new Token(tokenString, TokenType.FAIL, position);
+        
+        // If not keyword, assume it is an identifier
+        return new Token(tokenString, TokenType.IDENTIFIER, position);
+    }
+    
+    private void skipLine() {
+        while(!reader.current().isEOF() && !reader.current().isNewLine()) reader.consume();
+        consumeWhitespace();
+    }
+    
+    private void consumeWhitespace() {
+        while(!reader.current().isEOF() && reader.current().isWhitespace()) reader.consume(); // Consume whitespace.
+    }
+    
+    private void skipTo(String s) throws EOFException {
+        SourcePosition begin = reader.getPosition();
+        while(!reader.current().isEOF()) {
+            if(reader.matchesString(s, true)) {
+                consumeWhitespace();
+                return;
+            }
+            reader.consume();
+        }
+        throw new EOFException("No end of expression found.", begin);
+    }
+    
+    private boolean isNumberLike() {
+        return reader.current().isDigit()
+               || reader.current().is('_', '.', 'E');
+    }
+    
+    private boolean isNumberStart() {
+        return reader.current().isDigit()
+               || reader.current().is('.') && reader.peek().isDigit();
+    }
+    
+    public boolean isSyntaxSignificant(char c) {
+        return syntaxSignificant.contains(c);
+    }
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/LookaheadStream.java

@@ -0,0 +1,84 @@
+package com.dfsek.terra.addons.terrascript.lexer;
+
+
+
+public class LookaheadStream {
+    
+    private final String source;
+    
+    private int index;
+    
+    private SourcePosition position = new SourcePosition(1, 1);
+    
+    public LookaheadStream(String source) {
+        this.source = source;
+    }
+    
+    /**
+     * Get the current character without consuming it.
+     *
+     * @return current character
+     */
+    public Char current() {
+        return new Char(source.charAt(index), position);
+    }
+    
+    /**
+     * Consume and return one character.
+     *
+     * @return Character that was consumed.
+     */
+    public Char consume() {
+        Char consumed = current();
+        incrementIndex(1);
+        return consumed;
+    }
+    
+    /**
+     * @return The next character in sequence.
+     */
+    public Char peek() {
+        int index = this.index + 1;
+        if (index + 1 >= source.length()) return null;
+        return new Char(source.charAt(index), getPositionAfter(1));
+    }
+    
+    /**
+     * Determines if the contained sequence of characters matches the string
+     *
+     * @param check Input string to check against
+     * @param consumeIfMatched Whether to consume the string if there is a match
+     * @return If the string matches
+     */
+    public boolean matchesString(String check, boolean consumeIfMatched) {
+        boolean matches = check.equals(source.substring(index, Math.min(index + check.length(), source.length())));
+        if (matches && consumeIfMatched) incrementIndex(check.length());
+        return matches;
+    }
+    
+    /**
+     * @return Current position within the source file
+     */
+    public SourcePosition getPosition() {
+        return position;
+    }
+    
+    private void incrementIndex(int amount) {
+        position = getPositionAfter(amount);
+        index = Math.min(index + amount, source.length() - 1);
+    }
+    
+    private SourcePosition getPositionAfter(int chars) {
+        if (chars < 0) throw new IllegalArgumentException("Negative values are not allowed");
+        int line = position.line();
+        int column = position.column();
+        for (int i = index; i < Math.min(index + chars, source.length() - 1); i++) {
+            if (source.charAt(i) == '\n') {
+                line++;
+                column = 0;
+            }
+            column++;
+        }
+        return new SourcePosition(line, column);
+    }
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/SourcePosition.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2020-2021 Polyhedral Development
+ *
+ * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in this module's root directory.
+ */
+
+package com.dfsek.terra.addons.terrascript.lexer;
+
+import java.util.Objects;
+
+
+public record SourcePosition(int line, int column) {
+    
+    @Override
+    public String toString() {
+        return "line " + line + ", column " + column;
+    }
+    
+    @Override
+    public boolean equals(Object o) {
+        if(this == o) return true;
+        if(o == null || getClass() != o.getClass()) return false;
+        SourcePosition that = (SourcePosition) o;
+        return line == that.line && column == that.column;
+    }
+    
+    @Override
+    public int hashCode() {
+        return Objects.hash(line, column);
+    }
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/Token.java

@@ -5,14 +5,14 @@
  * reference the LICENSE file in this module's root directory.
  */
 
-package com.dfsek.terra.addons.terrascript.tokenizer;
+package com.dfsek.terra.addons.terrascript.lexer;
 
 public class Token {
     private final String content;
-    private final Type type;
-    private final Position start;
+    private final TokenType type;
+    private final SourcePosition start;
     
-    public Token(String content, Type type, Position start) {
+    public Token(String content, TokenType type, SourcePosition start) {
         this.content = content;
         this.type = type;
         this.start = start;
@@ -23,7 +23,7 @@ public class Token {
         return type + ": '" + content + "'";
     }
     
-    public Type getType() {
+    public TokenType getType() {
         return type;
     }
     
@@ -31,63 +31,68 @@ public class Token {
         return content;
     }
     
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return start;
     }
     
     public boolean isConstant() {
-        return this.type.equals(Type.NUMBER) || this.type.equals(Type.STRING) || this.type.equals(Type.BOOLEAN);
+        return this.type.equals(TokenType.NUMBER) || this.type.equals(TokenType.STRING) || this.type.equals(TokenType.BOOLEAN);
+    }
+    
+    public boolean isType(TokenType type) {
+        return type == getType();
+    }
+    
+    public boolean isType(TokenType... types) {
+        for (TokenType t : types) if (isType(t)) return true;
+        return false;
     }
     
     public boolean isBinaryOperator() {
-        return type.equals(Type.ADDITION_OPERATOR)
-               || type.equals(Type.SUBTRACTION_OPERATOR)
-               || type.equals(Type.MULTIPLICATION_OPERATOR)
-               || type.equals(Type.DIVISION_OPERATOR)
-               || type.equals(Type.EQUALS_OPERATOR)
-               || type.equals(Type.NOT_EQUALS_OPERATOR)
-               || type.equals(Type.LESS_THAN_OPERATOR)
-               || type.equals(Type.GREATER_THAN_OPERATOR)
-               || type.equals(Type.LESS_THAN_OR_EQUALS_OPERATOR)
-               || type.equals(Type.GREATER_THAN_OR_EQUALS_OPERATOR)
-               || type.equals(Type.BOOLEAN_OR)
-               || type.equals(Type.BOOLEAN_AND)
-               || type.equals(Type.MODULO_OPERATOR);
+        return type.equals(TokenType.PLUS)
+               || type.equals(TokenType.MINUS)
+               || type.equals(TokenType.STAR)
+               || type.equals(TokenType.FORWARD_SLASH)
+               || type.equals(TokenType.EQUALS_EQUALS)
+               || type.equals(TokenType.BANG_EQUALS)
+               || type.equals(TokenType.LESS)
+               || type.equals(TokenType.GREATER)
+               || type.equals(TokenType.LESS_EQUALS)
+               || type.equals(TokenType.GREATER_EQUAL)
+               || type.equals(TokenType.BOOLEAN_OR)
+               || type.equals(TokenType.BOOLEAN_AND)
+               || type.equals(TokenType.MODULO_OPERATOR);
     }
     
     public boolean isStrictNumericOperator() {
-        return type.equals(Type.SUBTRACTION_OPERATOR)
-               || type.equals(Type.MULTIPLICATION_OPERATOR)
-               || type.equals(Type.DIVISION_OPERATOR)
-               || type.equals(Type.GREATER_THAN_OPERATOR)
-               || type.equals(Type.LESS_THAN_OPERATOR)
-               || type.equals(Type.LESS_THAN_OR_EQUALS_OPERATOR)
-               || type.equals(Type.GREATER_THAN_OR_EQUALS_OPERATOR)
-               || type.equals(Type.MODULO_OPERATOR);
+        return type.equals(TokenType.MINUS)
+               || type.equals(TokenType.STAR)
+               || type.equals(TokenType.FORWARD_SLASH)
+               || type.equals(TokenType.GREATER)
+               || type.equals(TokenType.LESS)
+               || type.equals(TokenType.LESS_EQUALS)
+               || type.equals(TokenType.GREATER_EQUAL)
+               || type.equals(TokenType.MODULO_OPERATOR);
     }
     
     public boolean isStrictBooleanOperator() {
-        return type.equals(Type.BOOLEAN_AND)
-               || type.equals(Type.BOOLEAN_OR);
+        return type.equals(TokenType.BOOLEAN_AND)
+               || type.equals(TokenType.BOOLEAN_OR);
     }
     
     public boolean isVariableDeclaration() {
-        return type.equals(Type.STRING_VARIABLE)
-               || type.equals(Type.BOOLEAN_VARIABLE)
-               || type.equals(Type.NUMBER_VARIABLE);
+        return type.equals(TokenType.TYPE_STRING)
+               || type.equals(TokenType.TYPE_BOOLEAN)
+               || type.equals(TokenType.TYPE_NUMBER);
     }
     
-    public boolean isLoopLike() {
-        return type.equals(Type.IF_STATEMENT)
-               || type.equals(Type.WHILE_LOOP)
-               || type.equals(Type.FOR_LOOP);
+    public boolean isControlStructure() {
+        return type.equals(TokenType.IF_STATEMENT)
+               || type.equals(TokenType.WHILE_LOOP)
+               || type.equals(TokenType.FOR_LOOP);
     }
     
-    public boolean isIdentifier() {
-        return type.equals(Type.IDENTIFIER);
-    }
-    
-    public enum Type {
+    public enum TokenType {
         /**
          * Function identifier or language keyword
          */
@@ -108,11 +113,11 @@ public class Token {
         /**
          * Beginning of group
          */
-        GROUP_BEGIN,
+        OPEN_PAREN,
         /**
          * Ending of group
          */
-        GROUP_END,
+        CLOSE_PAREN,
         /**
          * End of statement
          */
@@ -136,43 +141,43 @@ public class Token {
         /**
          * Boolean equals operator
          */
-        EQUALS_OPERATOR,
+        EQUALS_EQUALS,
         /**
          * Boolean not equals operator
          */
-        NOT_EQUALS_OPERATOR,
+        BANG_EQUALS,
         /**
          * Boolean greater than operator
          */
-        GREATER_THAN_OPERATOR,
+        GREATER,
         /**
          * Boolean less than operator
          */
-        LESS_THAN_OPERATOR,
+        LESS,
         /**
          * Boolean greater than or equal to operator
          */
-        GREATER_THAN_OR_EQUALS_OPERATOR,
+        GREATER_EQUAL,
         /**
          * Boolean less than or equal to operator
          */
-        LESS_THAN_OR_EQUALS_OPERATOR,
+        LESS_EQUALS,
         /**
          * Addition/concatenation operator
          */
-        ADDITION_OPERATOR,
+        PLUS,
         /**
          * Subtraction operator
          */
-        SUBTRACTION_OPERATOR,
+        MINUS,
         /**
          * Multiplication operator
          */
-        MULTIPLICATION_OPERATOR,
+        STAR,
         /**
          * Division operator
          */
-        DIVISION_OPERATOR,
+        FORWARD_SLASH,
         /**
          * Modulo operator.
          */
@@ -180,7 +185,7 @@ public class Token {
         /**
          * Boolean not operator
          */
-        BOOLEAN_NOT,
+        BANG,
         /**
          * Boolean or
          */
@@ -192,15 +197,19 @@ public class Token {
         /**
          * Numeric variable declaration
          */
-        NUMBER_VARIABLE,
+        TYPE_NUMBER,
         /**
          * String variable declaration
          */
-        STRING_VARIABLE,
+        TYPE_STRING,
         /**
          * Boolean variable declaration
          */
-        BOOLEAN_VARIABLE,
+        TYPE_BOOLEAN,
+        /**
+         * Void type declaration
+         */
+        TYPE_VOID,
         /**
          * If statement declaration
          */
@@ -232,6 +241,10 @@ public class Token {
         /**
          * Else keyword
          */
-        ELSE
+        ELSE,
+        /**
+         * End of file
+         */
+        END_OF_FILE
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/exceptions/EOFException.java

@@ -5,11 +5,11 @@
  * reference the LICENSE file in this module's root directory.
  */
 
-package com.dfsek.terra.addons.terrascript.tokenizer.exceptions;
+package com.dfsek.terra.addons.terrascript.lexer.exceptions;
 
 import java.io.Serial;
 
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 
 
 public class EOFException extends TokenizerException {
@@ -17,11 +17,11 @@ public class EOFException extends TokenizerException {
     @Serial
     private static final long serialVersionUID = 3980047409902809440L;
     
-    public EOFException(String message, Position position) {
+    public EOFException(String message, SourcePosition position) {
         super(message, position);
     }
     
-    public EOFException(String message, Position position, Throwable cause) {
+    public EOFException(String message, SourcePosition position, Throwable cause) {
         super(message, position, cause);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/exceptions/FormatException.java

@@ -5,11 +5,11 @@
  * reference the LICENSE file in this module's root directory.
  */
 
-package com.dfsek.terra.addons.terrascript.tokenizer.exceptions;
+package com.dfsek.terra.addons.terrascript.lexer.exceptions;
 
 import java.io.Serial;
 
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 
 
 public class FormatException extends TokenizerException {
@@ -17,11 +17,11 @@ public class FormatException extends TokenizerException {
     @Serial
     private static final long serialVersionUID = -791308012940744455L;
     
-    public FormatException(String message, Position position) {
+    public FormatException(String message, SourcePosition position) {
         super(message, position);
     }
     
-    public FormatException(String message, Position position, Throwable cause) {
+    public FormatException(String message, SourcePosition position, Throwable cause) {
         super(message, position, cause);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/lexer/exceptions/TokenizerException.java

@@ -5,12 +5,12 @@
  * reference the LICENSE file in this module's root directory.
  */
 
-package com.dfsek.terra.addons.terrascript.tokenizer.exceptions;
+package com.dfsek.terra.addons.terrascript.lexer.exceptions;
 
 import java.io.Serial;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public abstract class TokenizerException extends ParseException {
@@ -18,11 +18,11 @@ public abstract class TokenizerException extends ParseException {
     @Serial
     private static final long serialVersionUID = 2792384010083575420L;
     
-    public TokenizerException(String message, Position position) {
+    public TokenizerException(String message, SourcePosition position) {
         super(message, position);
     }
     
-    public TokenizerException(String message, Position position, Throwable cause) {
+    public TokenizerException(String message, SourcePosition position, Throwable cause) {
         super(message, position, cause);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/Parser.java

@@ -9,24 +9,26 @@ package com.dfsek.terra.addons.terrascript.parser;
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Consumer;
+import java.util.function.Function;
 
+import com.dfsek.terra.addons.terrascript.lexer.Lexer;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.lexer.Token;
+import com.dfsek.terra.addons.terrascript.lexer.Token.TokenType;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
 import com.dfsek.terra.addons.terrascript.parser.lang.Block;
 import com.dfsek.terra.addons.terrascript.parser.lang.Executable;
-import com.dfsek.terra.addons.terrascript.parser.lang.Item;
-import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable.ReturnType;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression.ReturnType;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope.ScopeBuilder;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.BooleanConstant;
-import com.dfsek.terra.addons.terrascript.parser.lang.constants.ConstantExpression;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.NumericConstant;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.StringConstant;
-import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
+import com.dfsek.terra.addons.terrascript.parser.lang.functions.UserDefinedFunctionBuilder;
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow.BreakKeyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow.ContinueKeyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow.FailKeyword;
@@ -34,7 +36,6 @@ import com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow.ReturnKeywor
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.looplike.ForKeyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.looplike.IfKeyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.keywords.looplike.WhileKeyword;
-import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BooleanAndOperation;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BooleanNotOperation;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BooleanOrOperation;
@@ -58,30 +59,16 @@ import com.dfsek.terra.addons.terrascript.parser.lang.variables.assign.VariableA
 import com.dfsek.terra.addons.terrascript.parser.lang.variables.reference.BoolVariableReferenceNode;
 import com.dfsek.terra.addons.terrascript.parser.lang.variables.reference.NumVariableReferenceNode;
 import com.dfsek.terra.addons.terrascript.parser.lang.variables.reference.StrVariableReferenceNode;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
-import com.dfsek.terra.addons.terrascript.tokenizer.Token;
-import com.dfsek.terra.addons.terrascript.tokenizer.Tokenizer;
 import com.dfsek.terra.api.util.generic.pair.Pair;
 
 
-@SuppressWarnings("unchecked")
 public class Parser {
-    private final String data;
-    private final Map<String, FunctionBuilder<? extends Function<?>>> functions = new HashMap<>();
     private final List<String> ignoredFunctions = new ArrayList<>();
     
-    public Parser(String data) {
-        this.data = data;
-    }
+    private final Lexer lexer;
     
-    public Parser registerFunction(String name, FunctionBuilder<? extends Function<?>> functionBuilder) {
-        functions.put(name, functionBuilder);
-        return this;
-    }
-    
-    public Parser ignoreFunction(String name) {
-        ignoredFunctions.add(name);
-        return this;
+    public Parser(Lexer lexer) {
+        this.lexer = lexer;
     }
     
     /**
@@ -91,378 +78,447 @@ public class Parser {
      *
      * @throws ParseException If parsing fails.
      */
-    public Executable parse() {
-        ScopeBuilder scopeBuilder = new ScopeBuilder();
-        return new Executable(parseBlock(new Tokenizer(data), false, scopeBuilder), scopeBuilder);
+    public Executable parse(ScopeBuilder scopeBuilder) {
+        return new Executable(parseBlock(scopeBuilder, ReturnType.VOID), scopeBuilder);
     }
     
-    private Keyword<?> parseLoopLike(Tokenizer tokens, boolean loop, ScopeBuilder scopeBuilder) throws ParseException {
-        
-        Token identifier = tokens.consume();
-        ParserUtil.checkType(identifier, Token.Type.IF_STATEMENT, Token.Type.WHILE_LOOP, Token.Type.FOR_LOOP);
-        
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_BEGIN);
-        
-        return switch(identifier.getType()) {
-            case FOR_LOOP -> parseForLoop(tokens, identifier.getPosition(), scopeBuilder);
-            case IF_STATEMENT -> parseIfStatement(tokens, identifier.getPosition(), loop, scopeBuilder);
-            case WHILE_LOOP -> parseWhileLoop(tokens, identifier.getPosition(), scopeBuilder);
-            default -> throw new UnsupportedOperationException(
-                    "Unknown keyword " + identifier.getContent() + ": " + identifier.getPosition());
-        };
+    private WhileKeyword parseWhileLoop(ScopeBuilder scopeBuilder) {
+        SourcePosition start = lexer.consume("Expected 'while' keyword at beginning of while loop", TokenType.WHILE_LOOP).getPosition();
+        lexer.consume("Expected '(' proceeding 'while' keyword", TokenType.OPEN_PAREN);
+        scopeBuilder = scopeBuilder.innerLoopScope();
+        Expression<?> condition = parseExpression(scopeBuilder);
+        ParserUtil.ensureReturnType(condition, Expression.ReturnType.BOOLEAN);
+        lexer.consume("Expected ')' proceeding while loop condition", TokenType.CLOSE_PAREN);
+        return new WhileKeyword(parseStatementBlock(scopeBuilder, ReturnType.VOID), (Expression<Boolean>) condition,
+                                start); // While loop
     }
     
-    private WhileKeyword parseWhileLoop(Tokenizer tokens, Position start, ScopeBuilder scopeBuilder) {
-        Returnable<?> first = parseExpression(tokens, true, scopeBuilder);
-        ParserUtil.checkReturnType(first, Returnable.ReturnType.BOOLEAN);
+    private IfKeyword parseIfStatement(ScopeBuilder scopeBuilder) {
+        SourcePosition start = lexer.consume("Expected 'if' keyword at beginning of if statement", TokenType.IF_STATEMENT).getPosition();
+        lexer.consume("Expected '(' proceeding 'if' keyword", TokenType.OPEN_PAREN);
+        Expression<?> condition = parseExpression(scopeBuilder);
+        ParserUtil.ensureReturnType(condition, Expression.ReturnType.BOOLEAN);
         
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_END);
-        
-        return new WhileKeyword(parseStatementBlock(tokens, true, scopeBuilder), (Returnable<Boolean>) first, start); // While loop
-    }
-    
-    private IfKeyword parseIfStatement(Tokenizer tokens, Position start, boolean loop, ScopeBuilder scopeBuilder) {
-        Returnable<?> condition = parseExpression(tokens, true, scopeBuilder);
-        ParserUtil.checkReturnType(condition, Returnable.ReturnType.BOOLEAN);
-        
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_END);
+        lexer.consume("Expected ')' proceeding if statement condition", TokenType.CLOSE_PAREN);
         
         Block elseBlock = null;
-        Block statement = parseStatementBlock(tokens, loop, scopeBuilder);
+        Block statement = parseStatementBlock(scopeBuilder, ReturnType.VOID);
         
-        List<Pair<Returnable<Boolean>, Block>> elseIf = new ArrayList<>();
+        List<Pair<Expression<Boolean>, Block>> elseIf = new ArrayList<>();
         
-        while(tokens.hasNext() && tokens.get().getType().equals(Token.Type.ELSE)) {
-            tokens.consume(); // Consume else.
-            if(tokens.get().getType().equals(Token.Type.IF_STATEMENT)) {
-                tokens.consume(); // Consume if.
-                Returnable<?> elseCondition = parseExpression(tokens, true, scopeBuilder);
-                ParserUtil.checkReturnType(elseCondition, Returnable.ReturnType.BOOLEAN);
-                elseIf.add(Pair.of((Returnable<Boolean>) elseCondition, parseStatementBlock(tokens, loop, scopeBuilder)));
+        while(lexer.hasNext() && lexer.current().isType(TokenType.ELSE)) {
+            lexer.consumeUnchecked(); // Consume else.
+            if(lexer.current().isType(TokenType.IF_STATEMENT)) {
+                lexer.consumeUnchecked(); // Consume if.
+                Expression<?> elseCondition = parseExpression(scopeBuilder);
+                ParserUtil.ensureReturnType(elseCondition, Expression.ReturnType.BOOLEAN);
+                elseIf.add(Pair.of((Expression<Boolean>) elseCondition, parseStatementBlock(scopeBuilder, ReturnType.VOID)));
             } else {
-                elseBlock = parseStatementBlock(tokens, loop, scopeBuilder);
+                elseBlock = parseStatementBlock(scopeBuilder, ReturnType.VOID);
                 break; // Else must be last.
             }
         }
         
-        return new IfKeyword(statement, (Returnable<Boolean>) condition, elseIf, elseBlock, start); // If statement
+        return new IfKeyword(statement, (Expression<Boolean>) condition, elseIf, elseBlock, start); // If statement
     }
     
-    private Block parseStatementBlock(Tokenizer tokens, boolean loop, ScopeBuilder scopeBuilder) {
-        
-        if(tokens.get().getType().equals(Token.Type.BLOCK_BEGIN)) {
-            ParserUtil.checkType(tokens.consume(), Token.Type.BLOCK_BEGIN);
-            Block block = parseBlock(tokens, loop, scopeBuilder);
-            ParserUtil.checkType(tokens.consume(), Token.Type.BLOCK_END);
+    private Block parseStatementBlock(ScopeBuilder scopeBuilder, ReturnType blockReturnType) {
+        if(lexer.current().isType(TokenType.BLOCK_BEGIN)) {
+            lexer.consumeUnchecked();
+            Block block = parseBlock(scopeBuilder, blockReturnType);
+            lexer.consume("Expected block end '}' after block statements", TokenType.BLOCK_END);
             return block;
         } else {
-            Position position = tokens.get().getPosition();
-            Block block = new Block(Collections.singletonList(parseItem(tokens, loop, scopeBuilder)), position);
-            ParserUtil.checkType(tokens.consume(), Token.Type.STATEMENT_END);
-            return block;
+            SourcePosition position = lexer.current().getPosition();
+            return new Block(Collections.singletonList(parseStatement(scopeBuilder)), position, blockReturnType);
         }
     }
     
-    private ForKeyword parseForLoop(Tokenizer tokens, Position start, ScopeBuilder scopeBuilder) {
-        scopeBuilder = scopeBuilder.sub(); // new scope
-        Token f = tokens.get();
-        ParserUtil.checkType(f, Token.Type.NUMBER_VARIABLE, Token.Type.STRING_VARIABLE, Token.Type.BOOLEAN_VARIABLE, Token.Type.IDENTIFIER);
-        Item<?> initializer;
-        if(f.isVariableDeclaration()) {
-            VariableAssignmentNode<?> forVar = parseVariableDeclaration(tokens, scopeBuilder);
-            Token name = tokens.get();
-            if(functions.containsKey(name.getContent()) || scopeBuilder.contains(name.getContent()))
-                throw new ParseException(name.getContent() + " is already defined in this scope", name.getPosition());
-            initializer = forVar;
-        } else initializer = parseExpression(tokens, true, scopeBuilder);
-        ParserUtil.checkType(tokens.consume(), Token.Type.STATEMENT_END);
-        Returnable<?> conditional = parseExpression(tokens, true, scopeBuilder);
-        ParserUtil.checkReturnType(conditional, Returnable.ReturnType.BOOLEAN);
-        ParserUtil.checkType(tokens.consume(), Token.Type.STATEMENT_END);
+    private ForKeyword parseForLoop(ScopeBuilder scopeBuilder) {
+        SourcePosition start = lexer.consume("Expected 'for' keyword at beginning of for loop", TokenType.FOR_LOOP).getPosition();
+        lexer.consume("Expected '(' after 'for' keyword", TokenType.OPEN_PAREN);
+        scopeBuilder = scopeBuilder.innerLoopScope(); // new scope
         
-        Item<?> incrementer;
-        Token token = tokens.get();
-        if(scopeBuilder.contains(token.getContent())) { // Assume variable assignment
-            incrementer = parseAssignment(tokens, scopeBuilder);
-        } else incrementer = parseFunction(tokens, true, scopeBuilder);
+        Expression<?> initializer = switch(lexer.current().getType()) {
+            case TYPE_NUMBER, TYPE_STRING, TYPE_BOOLEAN -> {
+                Token type = lexer.consume("Expected type before declaration", TokenType.TYPE_STRING, TokenType.TYPE_NUMBER, TokenType.TYPE_BOOLEAN, TokenType.TYPE_VOID);
+                Token identifier = lexer.consume("Expected identifier after type", TokenType.IDENTIFIER);
+                Expression<?> expr = parseVariableDeclaration(scopeBuilder, type, identifier);
+                lexer.consume("Expected ';' after initializer within for loop", TokenType.STATEMENT_END);
+                yield expr;
+            }
+            case IDENTIFIER -> {
+                Expression<?> expr = parseAssignment(scopeBuilder);
+                lexer.consume("Expected ';' after initializer within for loop", TokenType.STATEMENT_END);
+                yield expr;
+            }
+            case STATEMENT_END -> {
+                lexer.consumeUnchecked();
+                yield Expression.NOOP;
+            }
+            default -> throw new ParseException("Unexpected token '" + lexer.current() + "', expected variable declaration or assignment", lexer.current().getPosition());
+        };
         
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_END);
+        Expression<?> conditional;
+        if (lexer.current().isType(TokenType.STATEMENT_END)) // If no conditional is provided, conditional defaults to true
+            conditional = new BooleanConstant(true, lexer.current().getPosition());
+        else
+            conditional = parseExpression(scopeBuilder);
+        ParserUtil.ensureReturnType(conditional, Expression.ReturnType.BOOLEAN);
+        lexer.consume("Expected ';' separator after conditional within for loop", TokenType.STATEMENT_END);
         
-        return new ForKeyword(parseStatementBlock(tokens, true, scopeBuilder), initializer, (Returnable<Boolean>) conditional, incrementer,
+        Expression<?> incrementer;
+        if(lexer.current().isType(TokenType.CLOSE_PAREN))
+            // If no incrementer is provided, do nothing
+            incrementer = Expression.NOOP;
+        else if(scopeBuilder.containsVariable(lexer.current().getContent())) // Assume variable assignment
+            incrementer = parseAssignment(scopeBuilder);
+        else
+            incrementer = parseFunctionInvocation(lexer.consume("Expected function call within for loop incrementer", TokenType.IDENTIFIER), scopeBuilder);
+        lexer.consume("Expected ')' after for loop incrementer", TokenType.CLOSE_PAREN);
+        
+        return new ForKeyword(parseStatementBlock(scopeBuilder, ReturnType.VOID), initializer, (Expression<Boolean>) conditional,
+                              incrementer,
                               start);
     }
     
-    private Returnable<?> parseExpression(Tokenizer tokens, boolean full, ScopeBuilder scopeBuilder) {
-        boolean booleanInverted = false; // Check for boolean not operator
-        boolean negate = false;
-        if(tokens.get().getType().equals(Token.Type.BOOLEAN_NOT)) {
-            booleanInverted = true;
-            tokens.consume();
-        } else if(tokens.get().getType().equals(Token.Type.SUBTRACTION_OPERATOR)) {
-            negate = true;
-            tokens.consume();
-        }
-        
-        Token id = tokens.get();
-        
-        ParserUtil.checkType(id, Token.Type.IDENTIFIER, Token.Type.BOOLEAN, Token.Type.STRING, Token.Type.NUMBER, Token.Type.GROUP_BEGIN);
-        
-        Returnable<?> expression;
-        if(id.isConstant()) {
-            expression = parseConstantExpression(tokens);
-        } else if(id.getType().equals(Token.Type.GROUP_BEGIN)) { // Parse grouped expression
-            expression = parseGroup(tokens, scopeBuilder);
-        } else {
-            if(functions.containsKey(id.getContent()))
-                expression = parseFunction(tokens, false, scopeBuilder);
-            else if(scopeBuilder.contains(id.getContent())) {
-                ParserUtil.checkType(tokens.consume(), Token.Type.IDENTIFIER);
-                String varId = id.getContent();
-                ReturnType varType = scopeBuilder.getType(varId);
-                expression = switch(varType) {
-                    case NUMBER -> new NumVariableReferenceNode(id.getPosition(), varType, scopeBuilder.getIndex(varId));
-                    case STRING -> new StrVariableReferenceNode(id.getPosition(), varType, scopeBuilder.getIndex(varId));
-                    case BOOLEAN -> new BoolVariableReferenceNode(id.getPosition(), varType, scopeBuilder.getIndex(varId));
-                    default -> throw new ParseException("Illegal type for variable reference: " + varType, id.getPosition());
-                };
-                
-            } else throw new ParseException("Unexpected token \" " + id.getContent() + "\"", id.getPosition());
-        }
-        
-        if(booleanInverted) { // Invert operation if boolean not detected
-            ParserUtil.checkReturnType(expression, Returnable.ReturnType.BOOLEAN);
-            expression = new BooleanNotOperation((Returnable<Boolean>) expression, expression.getPosition());
-        } else if(negate) {
-            ParserUtil.checkReturnType(expression, Returnable.ReturnType.NUMBER);
-            expression = new NegationOperation((Returnable<Number>) expression, expression.getPosition());
-        }
-        
-        if(full && tokens.get().isBinaryOperator()) { // Parse binary operations
-            return parseBinaryOperation(expression, tokens, scopeBuilder);
-        }
-        return expression;
+    private Expression<?> parseExpression(ScopeBuilder scopeBuilder) {
+        return parseLogicOr(scopeBuilder);
     }
     
-    private ConstantExpression<?> parseConstantExpression(Tokenizer tokens) {
-        Token constantToken = tokens.consume();
-        Position position = constantToken.getPosition();
-        switch(constantToken.getType()) {
-            case NUMBER:
-                String content = constantToken.getContent();
-                return new NumericConstant(content.contains(".") ? Double.parseDouble(content) : Integer.parseInt(content), position);
-            case STRING:
-                return new StringConstant(constantToken.getContent(), position);
-            case BOOLEAN:
-                return new BooleanConstant(Boolean.parseBoolean(constantToken.getContent()), position);
-            default:
-                throw new UnsupportedOperationException(
-                        "Unsupported constant token: " + constantToken.getType() + " at position: " + position);
-        }
+    private Expression<?> parseLogicOr(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseLogicAnd, scopeBuilder, (op) -> {
+            ParserUtil.ensureReturnType(op.left, ReturnType.BOOLEAN);
+            ParserUtil.ensureReturnType(op.right, ReturnType.BOOLEAN);
+        }, Map.of(TokenType.BOOLEAN_OR, (op) -> new BooleanOrOperation((Expression<Boolean>) op.left, (Expression<Boolean>) op.right, op.operator.getPosition())));
     }
     
-    private Returnable<?> parseGroup(Tokenizer tokens, ScopeBuilder scopeBuilder) {
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_BEGIN);
-        Returnable<?> expression = parseExpression(tokens, true, scopeBuilder); // Parse inside of group as a separate expression
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_END);
-        return expression;
+    private Expression<?> parseLogicAnd(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseEquality, scopeBuilder, (op) -> {
+            ParserUtil.ensureReturnType(op.left, ReturnType.BOOLEAN);
+            ParserUtil.ensureReturnType(op.right, ReturnType.BOOLEAN);
+        }, Map.of(TokenType.BOOLEAN_AND, (op) -> new BooleanAndOperation((Expression<Boolean>) op.left, (Expression<Boolean>) op.right, op.operator.getPosition())));
     }
     
-    private BinaryOperation<?, ?> parseBinaryOperation(Returnable<?> left, Tokenizer tokens,
-                                                       ScopeBuilder scopeBuilder) {
-        Token binaryOperator = tokens.consume();
-        ParserUtil.checkBinaryOperator(binaryOperator);
-        
-        Returnable<?> right = parseExpression(tokens, false, scopeBuilder);
-        
-        Token other = tokens.get();
-        if(ParserUtil.hasPrecedence(binaryOperator.getType(), other.getType())) {
-            return assemble(left, parseBinaryOperation(right, tokens, scopeBuilder), binaryOperator);
-        } else if(other.isBinaryOperator()) {
-            return parseBinaryOperation(assemble(left, right, binaryOperator), tokens, scopeBuilder);
-        }
-        return assemble(left, right, binaryOperator);
+    private Expression<?> parseEquality(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseComparison, scopeBuilder, Map.of(
+            TokenType.EQUALS_EQUALS, (op) -> new EqualsStatement((Expression<Object>) op.left, (Expression<Object>) op.right, op.operator.getPosition()),
+            TokenType.BANG_EQUALS, (op) -> new NotEqualsStatement((Expression<Object>) op.left, (Expression<Object>) op.right, op.operator.getPosition())
+        ));
     }
     
-    private BinaryOperation<?, ?> assemble(Returnable<?> left, Returnable<?> right, Token binaryOperator) {
-        if(binaryOperator.isStrictNumericOperator())
-            ParserUtil.checkArithmeticOperation(left, right, binaryOperator); // Numeric type checking
-        if(binaryOperator.isStrictBooleanOperator()) ParserUtil.checkBooleanOperation(left, right, binaryOperator); // Boolean type checking
-        switch(binaryOperator.getType()) {
-            case ADDITION_OPERATOR:
-                if(left.returnType().equals(Returnable.ReturnType.NUMBER) && right.returnType().equals(Returnable.ReturnType.NUMBER)) {
-                    return new NumberAdditionOperation((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
+    private Expression<?> parseComparison(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseTerm, scopeBuilder, (op) -> {
+            ParserUtil.ensureReturnType(op.left, ReturnType.NUMBER);
+            ParserUtil.ensureReturnType(op.right, ReturnType.NUMBER);
+        }, Map.of(
+            TokenType.LESS, (op) -> new LessThanStatement((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition()),
+            TokenType.LESS_EQUALS, (op) -> new LessThanOrEqualsStatement((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition()),
+            TokenType.GREATER, (op) -> new GreaterThanStatement((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition()),
+            TokenType.GREATER_EQUAL, (op) -> new GreaterOrEqualsThanStatement((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition())
+        ));
+    }
+    
+    private Expression<?> parseTerm(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseFactor, scopeBuilder, Map.of(
+        TokenType.MINUS, (op) -> {
+            ParserUtil.ensureReturnType(op.left, ReturnType.NUMBER);
+            ParserUtil.ensureReturnType(op.right, ReturnType.NUMBER);
+            return new SubtractionOperation((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition());
+        },
+        TokenType.PLUS, (op) -> {
+            if (op.left.returnType() == ReturnType.NUMBER && op.right.returnType() == ReturnType.NUMBER)
+                return new NumberAdditionOperation((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition());
+            else
+                return new ConcatenationOperation((Expression<Object>) op.left, (Expression<Object>) op.right, op.operator.getPosition());
+        }));
+    }
+    
+    private Expression<?> parseFactor(ScopeBuilder scopeBuilder) {
+        return parseLeftAssociativeBinaryOperation(this::parseUnary, scopeBuilder, (op) -> {
+           ParserUtil.ensureReturnType(op.left, ReturnType.NUMBER);
+           ParserUtil.ensureReturnType(op.right, ReturnType.NUMBER);
+        }, Map.of(
+            TokenType.STAR, (op) -> new MultiplicationOperation((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition()),
+            TokenType.FORWARD_SLASH, (op) -> new DivisionOperation((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition()),
+            TokenType.MODULO_OPERATOR, (op) -> new ModuloOperation((Expression<Number>) op.left, (Expression<Number>) op.right, op.operator.getPosition())
+        ));
+    }
+    
+    private Expression<?> parseUnary(ScopeBuilder scopeBuilder) {
+        if (lexer.current().isType(TokenType.BANG, TokenType.MINUS)) {
+            Token operator = lexer.consumeUnchecked();
+            Expression<?> right = parseUnary(scopeBuilder);
+            return switch(operator.getType()) {
+                case BANG -> {
+                    ParserUtil.ensureReturnType(right, ReturnType.BOOLEAN);
+                    yield new BooleanNotOperation((Expression<Boolean>) right, operator.getPosition());
                 }
-                return new ConcatenationOperation((Returnable<Object>) left, (Returnable<Object>) right, binaryOperator.getPosition());
-            case SUBTRACTION_OPERATOR:
-                return new SubtractionOperation((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case MULTIPLICATION_OPERATOR:
-                return new MultiplicationOperation((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case DIVISION_OPERATOR:
-                return new DivisionOperation((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case EQUALS_OPERATOR:
-                return new EqualsStatement((Returnable<Object>) left, (Returnable<Object>) right, binaryOperator.getPosition());
-            case NOT_EQUALS_OPERATOR:
-                return new NotEqualsStatement((Returnable<Object>) left, (Returnable<Object>) right, binaryOperator.getPosition());
-            case GREATER_THAN_OPERATOR:
-                return new GreaterThanStatement((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case LESS_THAN_OPERATOR:
-                return new LessThanStatement((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case GREATER_THAN_OR_EQUALS_OPERATOR:
-                return new GreaterOrEqualsThanStatement((Returnable<Number>) left, (Returnable<Number>) right,
-                                                        binaryOperator.getPosition());
-            case LESS_THAN_OR_EQUALS_OPERATOR:
-                return new LessThanOrEqualsStatement((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            case BOOLEAN_AND:
-                return new BooleanAndOperation((Returnable<Boolean>) left, (Returnable<Boolean>) right, binaryOperator.getPosition());
-            case BOOLEAN_OR:
-                return new BooleanOrOperation((Returnable<Boolean>) left, (Returnable<Boolean>) right, binaryOperator.getPosition());
-            case MODULO_OPERATOR:
-                return new ModuloOperation((Returnable<Number>) left, (Returnable<Number>) right, binaryOperator.getPosition());
-            default:
-                throw new UnsupportedOperationException("Unsupported binary operator: " + binaryOperator.getType());
+                case MINUS -> {
+                    ParserUtil.ensureReturnType(right, ReturnType.NUMBER);
+                    yield new NegationOperation((Expression<Number>) right, operator.getPosition());
+                }
+                default -> throw new IllegalStateException();
+            };
         }
+        return parsePrimary(scopeBuilder);
     }
     
-    private VariableAssignmentNode<?> parseVariableDeclaration(Tokenizer tokens, ScopeBuilder scopeBuilder) {
-        Token type = tokens.consume();
-        ParserUtil.checkType(type, Token.Type.STRING_VARIABLE, Token.Type.BOOLEAN_VARIABLE, Token.Type.NUMBER_VARIABLE);
+    private Expression<?> parsePrimary(ScopeBuilder scopeBuilder) {
+        Token token = lexer.consumeUnchecked();
+        return switch(token.getType()) {
+            case NUMBER -> {
+                String content = token.getContent();
+                yield new NumericConstant(content.contains(".") ? Double.parseDouble(content) : Integer.parseInt(content), token.getPosition());
+            }
+            case STRING -> new StringConstant(token.getContent(), token.getPosition());
+            case BOOLEAN -> new BooleanConstant(Boolean.parseBoolean(token.getContent()), token.getPosition());
+            case OPEN_PAREN -> {
+                Expression<?> expr = parseExpression(scopeBuilder);
+                lexer.consume("Missing ')' at end of expression group", TokenType.CLOSE_PAREN);
+                yield expr;
+            }
+            case IDENTIFIER -> {
+                if (scopeBuilder.containsFunction(token.getContent()))
+                    yield parseFunctionInvocation(token, scopeBuilder);
+                else if (scopeBuilder.containsVariable(token.getContent())) {
+                    ReturnType variableType = scopeBuilder.getVaraibleType(token.getContent());
+                    yield switch(variableType) {
+                        case NUMBER -> new NumVariableReferenceNode(token.getPosition(), variableType, scopeBuilder.getIndex(token.getContent()));
+                        case BOOLEAN -> new BoolVariableReferenceNode(token.getPosition(), variableType, scopeBuilder.getIndex(token.getContent()));
+                        case STRING -> new StrVariableReferenceNode(token.getPosition(), variableType, scopeBuilder.getIndex(token.getContent()));
+                        default -> throw new ParseException("Illegal type for variable reference: " + variableType, token.getPosition());
+                    };
+                }
+                throw new ParseException("Identifier '" + token.getContent() + "' is not defined in this scope", token.getPosition());
+            }
+            default -> throw new ParseException("Unexpected token '" + token.getContent() + "' when parsing expression", token.getPosition());
+        };
+    }
+    
+    private Expression<?> parseLeftAssociativeBinaryOperation(Function<ScopeBuilder, Expression<?>> higherPrecedence, ScopeBuilder scopeBuilder,
+                                                              Consumer<BinaryOperationInfo> init,
+                                                              Map<TokenType, Function<BinaryOperationInfo, Expression<?>>> operators) {
+        Expression<?> expr = higherPrecedence.apply(scopeBuilder);
+        TokenType[] opTypes = operators.keySet().toArray(new TokenType[0]);
+        while (lexer.current().isType(opTypes)) {
+            Token operator = lexer.consumeUnchecked();
+            Expression<?> right = higherPrecedence.apply(scopeBuilder);
+            BinaryOperationInfo op = new BinaryOperationInfo(expr, operator, right);
+            init.accept(op);
+            expr = operators.get(operator.getType()).apply(op);
+        }
+        return expr;
+    }
+    
+    private Expression<?> parseLeftAssociativeBinaryOperation(Function<ScopeBuilder, Expression<?>> higherPrecedence, ScopeBuilder scopeBuilder, Map<TokenType, Function<BinaryOperationInfo, Expression<?>>> operators) {
+        return parseLeftAssociativeBinaryOperation(higherPrecedence, scopeBuilder, (op) -> {}, operators);
+    }
+    
+    private record BinaryOperationInfo(Expression<?> left, Token operator, Expression<?> right) {}
+    
+    private Expression<?> parseDeclaration(ScopeBuilder scopeBuilder) {
+        Token type = lexer.consume("Expected type before declaration", TokenType.TYPE_STRING, TokenType.TYPE_NUMBER, TokenType.TYPE_BOOLEAN, TokenType.TYPE_VOID);
+        Token identifier = lexer.consume("Expected identifier after type", TokenType.IDENTIFIER);
         
-        Returnable.ReturnType returnType = ParserUtil.getVariableReturnType(type);
+        return switch(lexer.current().getType()) {
+            case ASSIGNMENT -> parseVariableDeclaration(scopeBuilder, type, identifier);
+            case OPEN_PAREN -> parseFunctionDeclaration(scopeBuilder, type, identifier);
+            default -> throw new ParseException("Expected '=' for variable assignment or '(' for function declaration after identifier '" + identifier.getContent() + "'", lexer.current().getPosition());
+        };
+    }
+    
+    
+    private Expression<?> parseVariableDeclaration(ScopeBuilder scopeBuilder, Token type, Token identifier) {
+        lexer.consume("Expected '=' after identifier '" + identifier.getContent() + "' for variable declaration", TokenType.ASSIGNMENT);
         
-        ParserUtil.checkVarType(type, returnType); // Check for type mismatch
-        Token identifier = tokens.consume();
-        ParserUtil.checkType(identifier, Token.Type.IDENTIFIER);
-        if(functions.containsKey(identifier.getContent()) || scopeBuilder.contains(identifier.getContent()))
+        if (!type.isVariableDeclaration()) throw new ParseException("Expected type specification at beginning of variable declaration", type.getPosition());
+        
+        if(scopeBuilder.containsVariable(identifier.getContent()))
             throw new ParseException(identifier.getContent() + " is already defined in this scope", identifier.getPosition());
-        ParserUtil.checkType(tokens.consume(), Token.Type.ASSIGNMENT);
         
-        Returnable<?> value = parseExpression(tokens, true, scopeBuilder);
-        ParserUtil.checkReturnType(value, returnType);
-
-        String id = identifier.getContent();
-
+        Expression<?> value = parseExpression(scopeBuilder);
+        ParserUtil.ensureReturnType(value, ParserUtil.getVariableReturnType(type));
+        
+        String variableName = identifier.getContent();
         return switch(value.returnType()) {
-            case NUMBER -> new NumAssignmentNode((Returnable<Number>) value, identifier.getPosition(), scopeBuilder.num(id));
-            case STRING -> new StrAssignmentNode((Returnable<String>) value, identifier.getPosition(), scopeBuilder.str(id));
-            case BOOLEAN -> new BoolAssignmentNode((Returnable<Boolean>) value, identifier.getPosition(), scopeBuilder.bool(id));
+            case NUMBER -> new NumAssignmentNode((Expression<Number>) value, identifier.getPosition(),
+                                                 scopeBuilder.declareNum(variableName));
+            case STRING -> new StrAssignmentNode((Expression<String>) value, identifier.getPosition(),
+                                                 scopeBuilder.declareStr(variableName));
+            case BOOLEAN -> new BoolAssignmentNode((Expression<Boolean>) value, identifier.getPosition(),
+                                                   scopeBuilder.declareBool(variableName));
             default -> throw new ParseException("Illegal type for variable declaration: " + type, value.getPosition());
         };
     }
     
-    private Block parseBlock(Tokenizer tokens, boolean loop, ScopeBuilder scopeBuilder) {
-        List<Item<?>> parsedItems = new ArrayList<>();
+    private Expression<?> parseFunctionDeclaration(ScopeBuilder scopeBuilder, Token type, Token identifier) {
+        lexer.consume("Expected '(' after identifier '" + identifier.getContent() + "' for function declaration", TokenType.OPEN_PAREN);
         
-        scopeBuilder = scopeBuilder.sub();
+        if(!(type.isType(TokenType.TYPE_STRING, TokenType.TYPE_BOOLEAN, TokenType.TYPE_NUMBER, TokenType.TYPE_VOID)))
+            throw new ParseException("Invalid function declaration return type specification " + type.getType(), type.getPosition());
         
-        Token first = tokens.get();
+        if(scopeBuilder.containsVariable(identifier.getContent()))
+            throw new ParseException(identifier.getContent() + " is already defined in this scope", identifier.getPosition());
         
-        while(tokens.hasNext()) {
-            Token token = tokens.get();
-            if(token.getType().equals(Token.Type.BLOCK_END)) break; // Stop parsing at block end.
-            Item<?> parsedItem = parseItem(tokens, loop, scopeBuilder);
-            if(parsedItem != Function.NULL) {
-                parsedItems.add(parsedItem);
-            }
-            if(tokens.hasNext() && !token.isLoopLike()) ParserUtil.checkType(tokens.consume(), Token.Type.STATEMENT_END);
+        ReturnType returnType = ParserUtil.getVariableReturnType(type);
+        
+        ScopeBuilder functionBodyScope = scopeBuilder.functionScope();
+        
+        // Declare parameter names into function body scope
+        List<Pair<Integer, ReturnType>> parameterInfo = getFunctionParameterDeclaration().stream().map(
+                arg -> Pair.of(switch(arg.getRight()) {
+                    case NUMBER -> functionBodyScope.declareNum(arg.getLeft());
+                    case BOOLEAN -> functionBodyScope.declareBool(arg.getLeft());
+                    case STRING -> functionBodyScope.declareStr(arg.getLeft());
+                    default -> throw new IllegalArgumentException("Unsupported parameter type: " + arg.getRight());
+                }, arg.getRight())).toList();
+        
+        Block body = parseStatementBlock(functionBodyScope, returnType);
+        
+        FunctionBuilder<?> functionBuilder = new UserDefinedFunctionBuilder<>(returnType, parameterInfo, body, functionBodyScope);
+        
+        scopeBuilder.registerFunction(identifier.getContent(), functionBuilder);
+        return Expression.NOOP;
+    }
+    
+    private List<Pair<String, ReturnType>> getFunctionParameterDeclaration() {
+        List<Pair<String, ReturnType>> parameters = new ArrayList<>();
+        while(lexer.current().getType() != TokenType.CLOSE_PAREN) {
+            // Parse parameter type
+            Token typeToken = lexer.consume("Expected function parameter type declaration", TokenType.TYPE_BOOLEAN, TokenType.TYPE_STRING, TokenType.TYPE_NUMBER);
+            ReturnType type = ParserUtil.getVariableReturnType(typeToken);
+            
+            // Parse parameter name
+            Token identifierToken = lexer.consume("Expected function parameter identifier", TokenType.IDENTIFIER);
+            String name = identifierToken.getContent();
+            
+            parameters.add(Pair.of(name, type));
+            
+            // Consume separator if present, trailing separators are allowed
+            if(lexer.current().isType(TokenType.SEPARATOR)) lexer.consumeUnchecked();
         }
-        return new Block(parsedItems, first.getPosition());
+        lexer.consume("Expected ')' after function parameter declaration", TokenType.CLOSE_PAREN);
+        return parameters;
     }
     
-    private Item<?> parseItem(Tokenizer tokens, boolean loop, ScopeBuilder scopeBuilder) {
-        Token token = tokens.get();
-        if(loop) ParserUtil.checkType(token, Token.Type.IDENTIFIER, Token.Type.IF_STATEMENT, Token.Type.WHILE_LOOP, Token.Type.FOR_LOOP,
-                                      Token.Type.NUMBER_VARIABLE, Token.Type.STRING_VARIABLE, Token.Type.BOOLEAN_VARIABLE,
-                                      Token.Type.RETURN, Token.Type.BREAK, Token.Type.CONTINUE, Token.Type.FAIL);
-        else ParserUtil.checkType(token, Token.Type.IDENTIFIER, Token.Type.IF_STATEMENT, Token.Type.WHILE_LOOP, Token.Type.FOR_LOOP,
-                                  Token.Type.NUMBER_VARIABLE, Token.Type.STRING_VARIABLE, Token.Type.BOOLEAN_VARIABLE, Token.Type.RETURN,
-                                  Token.Type.FAIL);
+    private Block parseBlock(ScopeBuilder scopeBuilder, ReturnType blockReturnType) {
+        List<Expression<?>> expressions = new ArrayList<>();
+        scopeBuilder = scopeBuilder.innerScope(); // Create new inner scope for the block
+        SourcePosition startPosition = lexer.current().getPosition();
         
-        if(token.isLoopLike()) { // Parse loop-like tokens (if, while, etc)
-            return parseLoopLike(tokens, loop, scopeBuilder);
-        } else if(token.isIdentifier()) { // Parse identifiers
-            if(scopeBuilder.contains(token.getContent())) { // Assume variable assignment
-                return parseAssignment(tokens, scopeBuilder);
-            } else return parseFunction(tokens, true, scopeBuilder);
-        } else if(token.isVariableDeclaration()) {
-            
-            return parseVariableDeclaration(tokens, scopeBuilder);
-            
-        } else if(token.getType().equals(Token.Type.RETURN)) return new ReturnKeyword(tokens.consume().getPosition());
-        else if(token.getType().equals(Token.Type.BREAK)) return new BreakKeyword(tokens.consume().getPosition());
-        else if(token.getType().equals(Token.Type.CONTINUE)) return new ContinueKeyword(tokens.consume().getPosition());
-        else if(token.getType().equals(Token.Type.FAIL)) return new FailKeyword(tokens.consume().getPosition());
-        else throw new UnsupportedOperationException("Unexpected token " + token.getType() + ": " + token.getPosition());
+        boolean hasReturn = false;
+        
+        // Parse each statement
+        while(lexer.hasNext() && !lexer.current().isType(TokenType.BLOCK_END)) {
+            Expression<?> expression = parseStatement(scopeBuilder);
+            if(expression != Expression.NOOP) {
+                expressions.add(expression);
+            }
+            if(expression instanceof ReturnKeyword returnKeyword) {
+                hasReturn = true;
+                if(returnKeyword.dataReturnType() != blockReturnType)
+                    throw new ParseException(
+                            "Invalid return type, expected " + blockReturnType + ", found " + returnKeyword.dataReturnType(),
+                            expression.getPosition());
+            }
+        }
+        
+        if(blockReturnType != ReturnType.VOID && !hasReturn)
+            throw new ParseException("Block does not contain a return statement, must return type " + blockReturnType, startPosition);
+        
+        return new Block(expressions, startPosition, blockReturnType);
     }
     
-    private VariableAssignmentNode<?> parseAssignment(Tokenizer tokens, ScopeBuilder scopeBuilder) {
-        Token identifier = tokens.consume();
+    private Expression<?> parseStatement(ScopeBuilder scopeBuilder) {
+        Token token = lexer.current();
+        Expression<?> expression = switch(token.getType()) {
+            case FOR_LOOP -> parseForLoop(scopeBuilder);
+            case IF_STATEMENT -> parseIfStatement(scopeBuilder);
+            case WHILE_LOOP -> parseWhileLoop(scopeBuilder);
+            case IDENTIFIER -> {
+                if(scopeBuilder.containsVariable(token.getContent())) yield parseAssignment(scopeBuilder); // Assume variable assignment
+                else yield parseFunctionInvocation(lexer.consumeUnchecked(), scopeBuilder);
+            }
+            case TYPE_NUMBER, TYPE_STRING, TYPE_BOOLEAN, TYPE_VOID -> parseDeclaration(scopeBuilder);
+            case RETURN -> parseReturn(scopeBuilder);
+            case BREAK -> {
+                if (!scopeBuilder.isInLoop()) throw new ParseException("Break statements can only be defined inside loops", token.getPosition());
+                yield new BreakKeyword(lexer.consumeUnchecked().getPosition());
+            }
+            case CONTINUE -> {
+                if (!scopeBuilder.isInLoop()) throw new ParseException("Continue statements can only be defined inside loops", token.getPosition());
+                yield new ContinueKeyword(lexer.consumeUnchecked().getPosition());
+            }
+            case FAIL -> new FailKeyword(lexer.consumeUnchecked().getPosition());
+            case STATEMENT_END -> Expression.NOOP;
+            default -> throw new UnsupportedOperationException("Unexpected token " + token.getType() + ": " + token.getPosition());
+        };
+        if(!token.isControlStructure() && expression != Expression.NOOP) lexer.consume("Expected ';' at end of statement", TokenType.STATEMENT_END);
+        return expression;
+    }
+    
+    private ReturnKeyword parseReturn(ScopeBuilder scopeBuilder) {
+        Token returnToken = lexer.consume("Expected 'return' keyword at beginning of return statement", TokenType.RETURN);
+        Expression<?> data = null;
+        if(!lexer.current().isType(TokenType.STATEMENT_END)) {
+            data = parseExpression(scopeBuilder);
+        }
+        return new ReturnKeyword(data, returnToken.getPosition());
+    }
+    
+    private VariableAssignmentNode<?> parseAssignment(ScopeBuilder scopeBuilder) {
+        Token identifier = lexer.consume("Expected identifier at beginning of assignment", TokenType.IDENTIFIER);
         
-        ParserUtil.checkType(identifier, Token.Type.IDENTIFIER);
+        lexer.consume("Expected '=' after identifier for variable assignment", TokenType.ASSIGNMENT);
         
-        ParserUtil.checkType(tokens.consume(), Token.Type.ASSIGNMENT);
-        
-        Returnable<?> value = parseExpression(tokens, true, scopeBuilder);
+        Expression<?> value = parseExpression(scopeBuilder);
         
         String id = identifier.getContent();
         
-        ParserUtil.checkReturnType(value, scopeBuilder.getType(id));
+        ParserUtil.ensureReturnType(value, scopeBuilder.getVaraibleType(id));
         
         ReturnType type = value.returnType();
         
         return switch(type) {
-            case NUMBER -> new NumAssignmentNode((Returnable<Number>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
-            case STRING -> new StrAssignmentNode((Returnable<String>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
-            case BOOLEAN -> new BoolAssignmentNode((Returnable<Boolean>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
+            case NUMBER -> new NumAssignmentNode((Expression<Number>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
+            case STRING -> new StrAssignmentNode((Expression<String>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
+            case BOOLEAN -> new BoolAssignmentNode((Expression<Boolean>) value, identifier.getPosition(), scopeBuilder.getIndex(id));
             default -> throw new ParseException("Illegal type for variable assignment: " + type, value.getPosition());
         };
     }
     
-    private Function<?> parseFunction(Tokenizer tokens, boolean fullStatement, ScopeBuilder scopeBuilder) {
-        Token identifier = tokens.consume();
-        ParserUtil.checkType(identifier, Token.Type.IDENTIFIER); // First token must be identifier
+    private Expression<?> parseFunctionInvocation(Token identifier, ScopeBuilder scopeBuilder) {
+        if(!scopeBuilder.containsFunction(identifier.getContent()))
+            throw new ParseException("Function '" + identifier.getContent() + "' is not defined in this scope", identifier.getPosition());
         
-        if(!functions.containsKey(identifier.getContent()))
-            throw new ParseException("No such function \"" + identifier.getContent() + "\"", identifier.getPosition());
+        FunctionBuilder<?> builder = scopeBuilder.getFunction(identifier.getContent());
         
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_BEGIN); // Second is body begin
+        lexer.consume("Expected '(' after identifier " + identifier.getContent(), TokenType.OPEN_PAREN); // Invocation starts with open paren
         
-        
-        List<Returnable<?>> args = getArgs(tokens, scopeBuilder); // Extract arguments, consume the rest.
-        
-        ParserUtil.checkType(tokens.consume(), Token.Type.GROUP_END); // Remove body end
-        
-        if(fullStatement) ParserUtil.checkType(tokens.get(), Token.Type.STATEMENT_END);
+        List<Expression<?>> args = new ArrayList<>();
+        while(!lexer.current().isType(TokenType.CLOSE_PAREN)) {
+            args.add(parseExpression(scopeBuilder));
+            if (lexer.current().isType(TokenType.CLOSE_PAREN)) break;
+            lexer.consume("Expected ',' between function arguments", TokenType.SEPARATOR);
+        }
+        lexer.consume("Expected ')' after function arguments", TokenType.CLOSE_PAREN);
         
         if(ignoredFunctions.contains(identifier.getContent())) {
-            return Function.NULL;
+            return Expression.NOOP;
         }
         
-        if(functions.containsKey(identifier.getContent())) {
-            FunctionBuilder<?> builder = functions.get(identifier.getContent());
-            
-            if(builder.argNumber() != -1 && args.size() != builder.argNumber())
-                throw new ParseException("Expected " + builder.argNumber() + " arguments, found " + args.size(), identifier.getPosition());
-            
-            for(int i = 0; i < args.size(); i++) {
-                Returnable<?> argument = args.get(i);
-                if(builder.getArgument(i) == null)
-                    throw new ParseException("Unexpected argument at position " + i + " in function " + identifier.getContent(),
-                                             identifier.getPosition());
-                ParserUtil.checkReturnType(argument, builder.getArgument(i));
-            }
-            return builder.build(args, identifier.getPosition());
+        if(builder.argNumber() != -1 && args.size() != builder.argNumber())
+            throw new ParseException("Expected " + builder.argNumber() + " arguments, found " + args.size(), identifier.getPosition());
+        
+        for(int i = 0; i < args.size(); i++) {
+            Expression<?> argument = args.get(i);
+            if(builder.getArgument(i) == null)
+                throw new ParseException("Unexpected argument at position " + i + " in function " + identifier.getContent(),
+                                         identifier.getPosition());
+            ParserUtil.ensureReturnType(argument, builder.getArgument(i));
         }
-        throw new UnsupportedOperationException("Unsupported function: " + identifier.getContent());
+        return builder.build(args, identifier.getPosition());
     }
     
-    private List<Returnable<?>> getArgs(Tokenizer tokens, ScopeBuilder scopeBuilder) {
-        List<Returnable<?>> args = new ArrayList<>();
-        
-        while(!tokens.get().getType().equals(Token.Type.GROUP_END)) {
-            args.add(parseExpression(tokens, true, scopeBuilder));
-            ParserUtil.checkType(tokens.get(), Token.Type.SEPARATOR, Token.Type.GROUP_END);
-            if(tokens.get().getType().equals(Token.Type.SEPARATOR)) tokens.consume();
-        }
-        return args;
-    }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/ParserUtil.java

@@ -12,104 +12,32 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import com.dfsek.terra.addons.terrascript.lexer.Token;
+import com.dfsek.terra.addons.terrascript.lexer.Token.TokenType;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Token;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public class ParserUtil {
     
-    private static final Map<Token.Type, Map<Token.Type, Boolean>> PRECEDENCE = new HashMap<>(); // If second has precedence, true.
-    private static final List<Token.Type> ARITHMETIC = Arrays.asList(Token.Type.ADDITION_OPERATOR, Token.Type.SUBTRACTION_OPERATOR,
-                                                                     Token.Type.MULTIPLICATION_OPERATOR, Token.Type.DIVISION_OPERATOR,
-                                                                     Token.Type.MODULO_OPERATOR);
-    private static final List<Token.Type> COMPARISON = Arrays.asList(Token.Type.EQUALS_OPERATOR, Token.Type.NOT_EQUALS_OPERATOR,
-                                                                     Token.Type.LESS_THAN_OPERATOR, Token.Type.LESS_THAN_OR_EQUALS_OPERATOR,
-                                                                     Token.Type.GREATER_THAN_OPERATOR,
-                                                                     Token.Type.GREATER_THAN_OR_EQUALS_OPERATOR);
+//    public static void ensureType(Token token, TokenType... expected) {
+//        for(TokenType type : expected) if(token.getType().equals(type)) return;
+//        throw new ParseException("Expected " + Arrays.toString(expected) + " but found " + token.getType(), token.getPosition());
+//    }
     
-    static { // Setup precedence
-        Map<Token.Type, Boolean> add = new HashMap<>(); // Addition/subtraction before Multiplication/division.
-        add.put(Token.Type.MULTIPLICATION_OPERATOR, true);
-        add.put(Token.Type.DIVISION_OPERATOR, true);
-        
-        PRECEDENCE.put(Token.Type.ADDITION_OPERATOR, add);
-        PRECEDENCE.put(Token.Type.SUBTRACTION_OPERATOR, add);
-        
-        Map<Token.Type, Boolean> numericBoolean = new HashMap<>();
-        
-        ARITHMETIC.forEach(op -> numericBoolean.put(op, true)); // Numbers before comparison
-        COMPARISON.forEach(op -> PRECEDENCE.put(op, numericBoolean));
-        
-        
-        Map<Token.Type, Boolean> booleanOps = new HashMap<>();
-        ARITHMETIC.forEach(op -> booleanOps.put(op, true)); // Everything before boolean
-        COMPARISON.forEach(op -> booleanOps.put(op, true));
-        
-        
-        PRECEDENCE.put(Token.Type.BOOLEAN_AND, booleanOps);
-        PRECEDENCE.put(Token.Type.BOOLEAN_OR, booleanOps);
+    public static void ensureReturnType(Expression<?> returnable, Expression.ReturnType... types) {
+        for(Expression.ReturnType type : types) if(returnable.returnType().equals(type)) return;
+        throw new ParseException("Invalid type " + returnable.returnType() + ", expected " + (types.length == 1 ? types[0].toString() : "one of " + Arrays.toString(types)), returnable.getPosition());
     }
     
-    public static void checkType(Token token, Token.Type... expected) {
-        for(Token.Type type : expected) if(token.getType().equals(type)) return;
-        throw new ParseException("Expected " + Arrays.toString(expected) + " but found " + token.getType(), token.getPosition());
-    }
-    
-    public static void checkReturnType(Returnable<?> returnable, Returnable.ReturnType... types) {
-        for(Returnable.ReturnType type : types) if(returnable.returnType().equals(type)) return;
-        throw new ParseException("Expected " + Arrays.toString(types) + " but found " + returnable.returnType(), returnable.getPosition());
-    }
-    
-    public static void checkArithmeticOperation(Returnable<?> left, Returnable<?> right, Token operation) {
-        if(!left.returnType().equals(Returnable.ReturnType.NUMBER) || !right.returnType().equals(Returnable.ReturnType.NUMBER)) {
-            throw new ParseException(
-                    "Operation " + operation.getType() + " not supported between " + left.returnType() + " and " + right.returnType(),
-                    operation.getPosition());
-        }
-    }
-    
-    public static void checkBooleanOperation(Returnable<?> left, Returnable<?> right, Token operation) {
-        if(!left.returnType().equals(Returnable.ReturnType.BOOLEAN) || !right.returnType().equals(Returnable.ReturnType.BOOLEAN)) {
-            throw new ParseException(
-                    "Operation " + operation.getType() + " not supported between " + left.returnType() + " and " + right.returnType(),
-                    operation.getPosition());
-        }
-    }
-    
-    public static void checkVarType(Token token, Returnable.ReturnType returnType) {
-        if(returnType.equals(Returnable.ReturnType.STRING) && token.getType().equals(Token.Type.STRING_VARIABLE)) return;
-        if(returnType.equals(Returnable.ReturnType.NUMBER) && token.getType().equals(Token.Type.NUMBER_VARIABLE)) return;
-        if(returnType.equals(Returnable.ReturnType.BOOLEAN) && token.getType().equals(Token.Type.BOOLEAN_VARIABLE)) return;
-        throw new ParseException("Type mismatch, cannot convert from " + returnType + " to " + token.getType(), token.getPosition());
-    }
-    
-    /**
-     * Checks if token is a binary operator
-     *
-     * @param token Token to check
-     *
-     * @throws ParseException If token isn't a binary operator
-     */
-    public static void checkBinaryOperator(Token token) {
-        if(!token.isBinaryOperator())
-            throw new ParseException("Expected binary operator, found " + token.getType(), token.getPosition());
-    }
-    
-    public static Returnable.ReturnType getVariableReturnType(Token varToken) {
+    public static Expression.ReturnType getVariableReturnType(Token varToken) {
         return switch(varToken.getType()) {
-            case NUMBER_VARIABLE -> Returnable.ReturnType.NUMBER;
-            case STRING_VARIABLE -> Returnable.ReturnType.STRING;
-            case BOOLEAN_VARIABLE -> Returnable.ReturnType.BOOLEAN;
+            case TYPE_NUMBER -> Expression.ReturnType.NUMBER;
+            case TYPE_STRING -> Expression.ReturnType.STRING;
+            case TYPE_BOOLEAN -> Expression.ReturnType.BOOLEAN;
+            case TYPE_VOID -> Expression.ReturnType.VOID;
             default -> throw new ParseException("Unexpected token " + varToken.getType() + "; expected variable declaration",
                                                 varToken.getPosition());
         };
     }
-    
-    public static boolean hasPrecedence(Token.Type first, Token.Type second) {
-        if(!PRECEDENCE.containsKey(first)) return false;
-        Map<Token.Type, Boolean> pre = PRECEDENCE.get(first);
-        if(!pre.containsKey(second)) return false;
-        return pre.get(second);
-    }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/exceptions/ParseException.java

@@ -9,30 +9,30 @@ package com.dfsek.terra.addons.terrascript.parser.exceptions;
 
 import java.io.Serial;
 
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 
 
 public class ParseException extends RuntimeException {
     @Serial
     private static final long serialVersionUID = 6744390543046766386L;
-    private final Position position;
+    private final SourcePosition position;
     
-    public ParseException(String message, Position position) {
+    public ParseException(String message, SourcePosition position) {
         super(message);
         this.position = position;
     }
     
-    public ParseException(String message, Position position, Throwable cause) {
+    public ParseException(String message, SourcePosition position, Throwable cause) {
         super(message, cause);
         this.position = position;
     }
     
     @Override
     public String getMessage() {
-        return super.getMessage() + ": " + position;
+        return "Error at " + position + ": " + super.getMessage();
     }
     
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Block.java

@@ -9,35 +9,43 @@ package com.dfsek.terra.addons.terrascript.parser.lang;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
 
 
-public class Block implements Item<Block.ReturnInfo<?>> {
-    private final List<Item<?>> items;
-    private final Position position;
+public class Block implements Expression<EvaluationInfo<?>> {
+    private final List<Expression<?>> items;
+    private final SourcePosition position;
+    private final ReturnType returnType;
     
-    public Block(List<Item<?>> items, Position position) {
+    public Block(List<Expression<?>> items, SourcePosition position, ReturnType returnType) {
         this.items = items;
         this.position = position;
+        this.returnType = returnType;
     }
     
     @Override
-    public ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        for(Item<?> item : items) {
-            Object result = item.apply(implementationArguments, scope);
-            if(result instanceof ReturnInfo<?> level) {
-                if(!level.getLevel().equals(ReturnLevel.NONE)) return level;
+    public ReturnType returnType() {
+        return returnType;
+    }
+    
+    @Override
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        for(Expression<?> item : items) {
+            Object result = item.evaluate(implementationArguments, scope);
+            if(result instanceof EvaluationInfo<?> evalInfo) {
+                if(!evalInfo.level().equals(EvaluationLevel.NONE)) return evalInfo;
             }
         }
-        return new ReturnInfo<>(ReturnLevel.NONE, null);
+        return new EvaluationInfo<>(EvaluationLevel.NONE, Expression.NOOP);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     
-    public enum ReturnLevel {
+    public enum EvaluationLevel {
         NONE(false),
         BREAK(false),
         CONTINUE(false),
@@ -46,7 +54,7 @@ public class Block implements Item<Block.ReturnInfo<?>> {
         
         private final boolean returnFast;
         
-        ReturnLevel(boolean returnFast) {
+        EvaluationLevel(boolean returnFast) {
             this.returnFast = returnFast;
         }
         
@@ -56,21 +64,6 @@ public class Block implements Item<Block.ReturnInfo<?>> {
     }
     
     
-    public static class ReturnInfo<T> {
-        private final ReturnLevel level;
-        private final T data;
-        
-        public ReturnInfo(ReturnLevel level, T data) {
-            this.level = level;
-            this.data = data;
-        }
-        
-        public ReturnLevel getLevel() {
-            return level;
-        }
-        
-        public T getData() {
-            return data;
-        }
+    public record EvaluationInfo<T extends Expression<?>>(EvaluationLevel level, T data) {
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Executable.java

@@ -7,13 +7,13 @@ import com.dfsek.terra.addons.terrascript.parser.lang.Scope.ScopeBuilder;
 public class Executable {
     private final Block script;
     private final ThreadLocal<Scope> scope;
-
+    
     public Executable(Block script, ScopeBuilder scopeBuilder) {
         this.script = script;
         this.scope = ThreadLocal.withInitial(scopeBuilder::build);
     }
-
+    
     public boolean execute(ImplementationArguments arguments) {
-        return script.apply(arguments, scope.get()).getLevel() != Block.ReturnLevel.FAIL;
+        return script.evaluate(arguments, scope.get()).level() != Block.EvaluationLevel.FAIL;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Expression.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2020-2021 Polyhedral Development
+ *
+ * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in this module's root directory.
+ */
+
+package com.dfsek.terra.addons.terrascript.parser.lang;
+
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+
+
+public interface Expression<T> {
+    Expression<Void> NOOP = new Expression<>() {
+        @Override
+        public ReturnType returnType() {
+            return ReturnType.VOID;
+        }
+        
+        @Override
+        public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
+            return null;
+        }
+        
+        @Override
+        public SourcePosition getPosition() {
+            return null;
+        }
+    };
+    
+    ReturnType returnType();
+    
+    T evaluate(ImplementationArguments implementationArguments, Scope scope);
+    
+    default double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
+        throw new UnsupportedOperationException("Cannot apply " + this + " as double");
+    }
+    
+    default boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
+        throw new UnsupportedOperationException("Cannot apply " + this + " as double");
+    }
+    
+    SourcePosition getPosition();
+    
+    
+    enum ReturnType {
+        NUMBER(true),
+        STRING(true),
+        BOOLEAN(false),
+        VOID(false),
+        OBJECT(false);
+        
+        private final boolean comparable;
+        
+        ReturnType(boolean comparable) {
+            this.comparable = comparable;
+        }
+        
+        public boolean isComparable() {
+            return comparable;
+        }
+    }
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/ImplementationArguments.java

@@ -8,7 +8,7 @@
 package com.dfsek.terra.addons.terrascript.parser.lang;
 
 /**
- * Arguments passed to {@link Item}s by the implementation
+ * Arguments passed to {@link Expression}s by the implementation
  */
 public interface ImplementationArguments {
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Item.java

@@ -1,25 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.parser.lang;
-
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
-
-
-public interface Item<T> {
-    T apply(ImplementationArguments implementationArguments, Scope scope);
-    
-    default double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
-        throw new UnsupportedOperationException("Cannot apply " + this + " as double");
-    }
-    
-    default boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
-        throw new UnsupportedOperationException("Cannot apply " + this + " as double");
-    }
-    
-    Position getPosition();
-}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Keyword.java

@@ -7,5 +7,5 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang;
 
-public interface Keyword<T> extends Returnable<T> {
+public interface Keyword<T> extends Expression<T> {
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Returnable.java

@@ -1,30 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.parser.lang;
-
-public interface Returnable<T> extends Item<T> {
-    ReturnType returnType();
-    
-    enum ReturnType {
-        NUMBER(true),
-        STRING(true),
-        BOOLEAN(false),
-        VOID(false),
-        OBJECT(false);
-        
-        private final boolean comparable;
-        
-        ReturnType(boolean comparable) {
-            this.comparable = comparable;
-        }
-        
-        public boolean isComparable() {
-            return comparable;
-        }
-    }
-}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Scope.java

@@ -6,7 +6,9 @@ import net.jafama.FastMath;
 import java.util.HashMap;
 import java.util.Map;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable.ReturnType;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression.ReturnType;
+import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
+import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.api.util.generic.pair.Pair;
 
 
@@ -46,28 +48,57 @@ public class Scope {
     }
     
     public static final class ScopeBuilder {
+        
+        private final Map<String, FunctionBuilder<? extends Function<?>>> functions;
         private final Map<String, Pair<Integer, ReturnType>> indices;
         private int numSize, boolSize, strSize = 0;
         private ScopeBuilder parent;
         
+        private boolean inLoop;
+        
         public ScopeBuilder() {
+            this.functions = new HashMap<>();
             this.indices = new HashMap<>();
         }
         
-        private ScopeBuilder(ScopeBuilder parent) {
+        private ScopeBuilder(ScopeBuilder parent, boolean inLoop) {
             this.parent = parent;
             this.numSize = parent.numSize;
             this.boolSize = parent.boolSize;
             this.strSize = parent.strSize;
+            this.functions = new HashMap<>(parent.functions);
             this.indices = new HashMap<>(parent.indices);
+            this.inLoop = inLoop;
+        }
+        
+        private ScopeBuilder(Map<String, FunctionBuilder<? extends Function<?>>> functions) {
+            this.functions = new HashMap<>(functions);
+            this.indices = new HashMap<>();
         }
         
         public Scope build() {
             return new Scope(numSize, boolSize, strSize);
         }
         
-        public ScopeBuilder sub() {
-            return new ScopeBuilder(this);
+        public ScopeBuilder innerScope() {
+            return new ScopeBuilder(this, inLoop);
+        }
+        
+        public ScopeBuilder innerLoopScope() { return new ScopeBuilder(this, true); }
+        
+        public ScopeBuilder functionScope()  { return new ScopeBuilder(functions); }
+        
+        public ScopeBuilder registerFunction(String name, FunctionBuilder<? extends Function<?>> functionBuilder) {
+            functions.put(name, functionBuilder);
+            return this;
+        }
+        
+        public boolean containsFunction(String functionName) {
+            return functions.containsKey(functionName);
+        }
+        
+        public FunctionBuilder<?> getFunction(String functionName) {
+            return functions.get(functionName);
         }
         
         private String check(String id) {
@@ -76,8 +107,12 @@ public class Scope {
             }
             return id;
         }
-
-        public int num(String id) {
+        
+        public boolean isInLoop() {
+            return inLoop;
+        }
+        
+        public int declareNum(String id) {
             int num = numSize;
             indices.put(check(id), Pair.of(num, ReturnType.NUMBER));
             numSize++;
@@ -85,7 +120,7 @@ public class Scope {
             return num;
         }
         
-        public int str(String id) {
+        public int declareStr(String id) {
             int str = strSize;
             indices.put(check(id), Pair.of(str, ReturnType.STRING));
             strSize++;
@@ -93,7 +128,7 @@ public class Scope {
             return str;
         }
         
-        public int bool(String id) {
+        public int declareBool(String id) {
             int bool = boolSize;
             indices.put(check(id), Pair.of(bool, ReturnType.BOOLEAN));
             boolSize++;
@@ -107,14 +142,14 @@ public class Scope {
                 parent.updateBoolSize(size);
             }
         }
-
+        
         private void updateNumSize(int size) {
             this.numSize = FastMath.max(numSize, size);
             if(parent != null) {
                 parent.updateNumSize(size);
             }
         }
-
+        
         private void updateStrSize(int size) {
             this.strSize = FastMath.max(strSize, size);
             if(parent != null) {
@@ -126,12 +161,11 @@ public class Scope {
             return indices.get(id).getLeft();
         }
         
-        public ReturnType getType(String id) {
+        public ReturnType getVaraibleType(String id) {
             return indices.get(id).getRight();
         }
         
-        
-        public boolean contains(String id) {
+        public boolean containsVariable(String id) {
             return indices.containsKey(id);
         }
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/Statement.java

@@ -1,11 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.parser.lang;
-
-public interface Statement extends Item<Boolean> {
-}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/constants/BooleanConstant.java

@@ -7,15 +7,15 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.constants;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BooleanConstant extends ConstantExpression<Boolean> {
     private final boolean constant;
-
-    public BooleanConstant(Boolean constant, Position position) {
+    
+    public BooleanConstant(Boolean constant, SourcePosition position) {
         super(constant, position);
         this.constant = constant;
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/constants/ConstantExpression.java

@@ -7,28 +7,28 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.constants;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public abstract class ConstantExpression<T> implements Returnable<T> {
+public abstract class ConstantExpression<T> implements Expression<T> {
     private final T constant;
-    private final Position position;
+    private final SourcePosition position;
     
-    public ConstantExpression(T constant, Position position) {
+    public ConstantExpression(T constant, SourcePosition position) {
         this.constant = constant;
         this.position = position;
     }
     
     @Override
-    public T apply(ImplementationArguments implementationArguments, Scope scope) {
+    public T evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return constant;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/constants/NumericConstant.java

@@ -7,16 +7,16 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.constants;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class NumericConstant extends ConstantExpression<Number> {
     private final double constant;
-
-    public NumericConstant(Number constant, Position position) {
+    
+    public NumericConstant(Number constant, SourcePosition position) {
         super(constant, position);
         this.constant = constant.doubleValue();
     }
@@ -27,7 +27,7 @@ public class NumericConstant extends ConstantExpression<Number> {
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.NUMBER;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/constants/StringConstant.java

@@ -7,17 +7,17 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.constants;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public class StringConstant extends ConstantExpression<String> {
-    public StringConstant(String constant, Position position) {
+    public StringConstant(String constant, SourcePosition position) {
         super(constant, position);
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.STRING;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.STRING;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/functions/Function.java

@@ -7,37 +7,20 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.functions;
 
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public interface Function<T> extends Returnable<T> {
-    Function<?> NULL = new Function<>() {
-        @Override
-        public ReturnType returnType() {
-            return null;
-        }
-
-        @Override
-        public Object apply(ImplementationArguments implementationArguments, Scope scope) {
-            return null;
-        }
-
-        @Override
-        public Position getPosition() {
-            return null;
-        }
-    };
+public interface Function<T> extends Expression<T> {
     
     @Override
     default double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
-        return ((Number) apply(implementationArguments, scope)).doubleValue();
+        return ((Number) evaluate(implementationArguments, scope)).doubleValue();
     }
     
     @Override
     default boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
-        return (Boolean) apply(implementationArguments, scope);
+        return (Boolean) evaluate(implementationArguments, scope);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/functions/FunctionBuilder.java

@@ -9,14 +9,17 @@ package com.dfsek.terra.addons.terrascript.parser.lang.functions;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public interface FunctionBuilder<T extends Function<?>> {
-    T build(List<Returnable<?>> argumentList, Position position);
+    T build(List<Expression<?>> argumentList, SourcePosition position);
     
+    /**
+     * @return Number of function arguments, -1 if the function uses a vararg at the end
+     */
     int argNumber();
     
-    Returnable.ReturnType getArgument(int position);
+    Expression.ReturnType getArgument(int position);
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/functions/FunctionSignature.java

@@ -0,0 +1,8 @@
+package com.dfsek.terra.addons.terrascript.parser.lang.functions;
+
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression.ReturnType;
+import com.dfsek.terra.api.util.generic.pair.Pair;
+
+
+public record FunctionSignature(ReturnType returnType, Pair<String, ReturnType>[] arguments) {
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/functions/UserDefinedFunctionBuilder.java

@@ -0,0 +1,74 @@
+package com.dfsek.terra.addons.terrascript.parser.lang.functions;
+
+import java.util.List;
+
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression.ReturnType;
+import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
+import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
+import com.dfsek.terra.addons.terrascript.parser.lang.Scope.ScopeBuilder;
+import com.dfsek.terra.api.util.generic.pair.Pair;
+
+
+public class UserDefinedFunctionBuilder<T extends Function<?>> implements FunctionBuilder<T> {
+    
+    private final ReturnType returnType;
+    private final List<Pair<Integer, ReturnType>> parameterInfo;
+    private final ScopeBuilder bodyScopeBuilder;
+    private final Block body;
+    
+    public UserDefinedFunctionBuilder(ReturnType returnType, List<Pair<Integer, ReturnType>> parameterInfo, Block body,
+                                      ScopeBuilder functionBodyScope) {
+        this.returnType = returnType;
+        this.bodyScopeBuilder = functionBodyScope;
+        this.body = body;
+        this.parameterInfo = parameterInfo;
+    }
+    
+    @Override
+    public T build(List<Expression<?>> argumentList, SourcePosition position) {
+        //noinspection unchecked
+        return (T) new Function() {
+            
+            private final ThreadLocal<Scope> threadLocalScope = ThreadLocal.withInitial(bodyScopeBuilder::build);
+            
+            @Override
+            public ReturnType returnType() {
+                return returnType;
+            }
+            
+            @Override
+            public Object evaluate(ImplementationArguments implementationArguments, Scope scope) {
+                Scope bodyScope = threadLocalScope.get();
+                // Pass arguments into scope of function body
+                for(int i = 0; i < argumentList.size(); i++) {
+                    Pair<Integer, ReturnType> paramInfo = parameterInfo.get(i);
+                    Expression<?> argExpression = argumentList.get(i);
+                    switch(paramInfo.getRight()) {
+                        case NUMBER -> bodyScope.setNum(paramInfo.getLeft(), argExpression.applyDouble(implementationArguments, scope));
+                        case BOOLEAN -> bodyScope.setBool(paramInfo.getLeft(), argExpression.applyBoolean(implementationArguments, scope));
+                        case STRING -> bodyScope.setStr(paramInfo.getLeft(), (String) argExpression.evaluate(implementationArguments, scope));
+                    }
+                }
+                return body.evaluate(implementationArguments, bodyScope).data().evaluate(implementationArguments, scope);
+            }
+            
+            @Override
+            public SourcePosition getPosition() {
+                return position;
+            }
+        };
+    }
+    
+    @Override
+    public int argNumber() {
+        return parameterInfo.size();
+    }
+    
+    @Override
+    public ReturnType getArgument(int position) {
+        return parameterInfo.get(position).getRight();
+    }
+}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/flow/BreakKeyword.java

@@ -7,27 +7,28 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class BreakKeyword implements Keyword<Block.ReturnInfo<?>> {
-    private final Position position;
+public class BreakKeyword implements Keyword<EvaluationInfo<?>> {
+    private final SourcePosition position;
     
-    public BreakKeyword(Position position) {
+    public BreakKeyword(SourcePosition position) {
         this.position = position;
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        return new Block.ReturnInfo<>(Block.ReturnLevel.BREAK, null);
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        return new EvaluationInfo<>(EvaluationLevel.BREAK, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/flow/ContinueKeyword.java

@@ -7,27 +7,28 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class ContinueKeyword implements Keyword<Block.ReturnInfo<?>> {
-    private final Position position;
+public class ContinueKeyword implements Keyword<EvaluationInfo<?>> {
+    private final SourcePosition position;
     
-    public ContinueKeyword(Position position) {
+    public ContinueKeyword(SourcePosition position) {
         this.position = position;
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        return new Block.ReturnInfo<>(Block.ReturnLevel.CONTINUE, null);
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        return new EvaluationInfo<>(EvaluationLevel.CONTINUE, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/flow/FailKeyword.java

@@ -7,27 +7,28 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class FailKeyword implements Keyword<Block.ReturnInfo<?>> {
-    private final Position position;
+public class FailKeyword implements Keyword<EvaluationInfo<?>> {
+    private final SourcePosition position;
     
-    public FailKeyword(Position position) {
+    public FailKeyword(SourcePosition position) {
         this.position = position;
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        return new Block.ReturnInfo<>(Block.ReturnLevel.FAIL, null);
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        return new EvaluationInfo<>(EvaluationLevel.FAIL, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/flow/ReturnKeyword.java

@@ -7,27 +7,34 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.flow;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import javax.annotation.Nullable;
+
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class ReturnKeyword implements Keyword<Block.ReturnInfo<?>> {
-    private final Position position;
+public class ReturnKeyword implements Keyword<EvaluationInfo<?>> {
+    private final SourcePosition position;
     
-    public ReturnKeyword(Position position) {
+    private final Expression<?> data;
+    
+    public ReturnKeyword(@Nullable Expression<?> data, SourcePosition position) {
+        this.data = data;
         this.position = position;
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        return new Block.ReturnInfo<>(Block.ReturnLevel.RETURN, null);
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        return new EvaluationInfo<>(EvaluationLevel.RETURN, data);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     
@@ -35,4 +42,12 @@ public class ReturnKeyword implements Keyword<Block.ReturnInfo<?>> {
     public ReturnType returnType() {
         return ReturnType.VOID;
     }
+    
+    public ReturnType dataReturnType() {
+        if(data != null) {
+            return data.returnType();
+        } else {
+            return ReturnType.VOID;
+        }
+    }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/looplike/ForKeyword.java

@@ -7,23 +7,24 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.looplike;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Item;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class ForKeyword implements Keyword<Block.ReturnInfo<?>> {
+public class ForKeyword implements Keyword<Block.EvaluationInfo<?>> {
     private final Block conditional;
-    private final Item<?> initializer;
-    private final Returnable<Boolean> statement;
-    private final Item<?> incrementer;
-    private final Position position;
+    private final Expression<?> initializer;
+    private final Expression<Boolean> statement;
+    private final Expression<?> incrementer;
+    private final SourcePosition position;
     
-    public ForKeyword(Block conditional, Item<?> initializer, Returnable<Boolean> statement, Item<?> incrementer, Position position) {
+    public ForKeyword(Block conditional, Expression<?> initializer, Expression<Boolean> statement, Expression<?> incrementer,
+                      SourcePosition position) {
         this.conditional = conditional;
         this.initializer = initializer;
         this.statement = statement;
@@ -32,19 +33,19 @@ public class ForKeyword implements Keyword<Block.ReturnInfo<?>> {
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        for(initializer.apply(implementationArguments, scope);
-            statement.apply(implementationArguments, scope);
-            incrementer.apply(implementationArguments, scope)) {
-            Block.ReturnInfo<?> level = conditional.apply(implementationArguments, scope);
-            if(level.getLevel().equals(Block.ReturnLevel.BREAK)) break;
-            if(level.getLevel().isReturnFast()) return level;
+    public Block.EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        for(initializer.evaluate(implementationArguments, scope);
+            statement.evaluate(implementationArguments, scope);
+            incrementer.evaluate(implementationArguments, scope)) {
+            Block.EvaluationInfo<?> level = conditional.evaluate(implementationArguments, scope);
+            if(level.level().equals(EvaluationLevel.BREAK)) break;
+            if(level.level().isReturnFast()) return level;
         }
-        return new Block.ReturnInfo<>(Block.ReturnLevel.NONE, null);
+        return new Block.EvaluationInfo<>(EvaluationLevel.NONE, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/looplike/IfKeyword.java

@@ -11,24 +11,25 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.util.generic.pair.Pair;
 
 
-public class IfKeyword implements Keyword<Block.ReturnInfo<?>> {
+public class IfKeyword implements Keyword<Block.EvaluationInfo<?>> {
     private final Block conditional;
-    private final Returnable<Boolean> statement;
-    private final Position position;
-    private final List<Pair<Returnable<Boolean>, Block>> elseIf;
+    private final Expression<Boolean> statement;
+    private final SourcePosition position;
+    private final List<Pair<Expression<Boolean>, Block>> elseIf;
     private final Block elseBlock;
     
-    public IfKeyword(Block conditional, Returnable<Boolean> statement, List<Pair<Returnable<Boolean>, Block>> elseIf,
-                     @Nullable Block elseBlock, Position position) {
+    public IfKeyword(Block conditional, Expression<Boolean> statement, List<Pair<Expression<Boolean>, Block>> elseIf,
+                     @Nullable Block elseBlock, SourcePosition position) {
         this.conditional = conditional;
         this.statement = statement;
         this.position = position;
@@ -37,21 +38,21 @@ public class IfKeyword implements Keyword<Block.ReturnInfo<?>> {
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        if(statement.apply(implementationArguments, scope)) return conditional.apply(implementationArguments, scope);
+    public Block.EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        if(statement.evaluate(implementationArguments, scope)) return conditional.evaluate(implementationArguments, scope);
         else {
-            for(Pair<Returnable<Boolean>, Block> pair : elseIf) {
-                if(pair.getLeft().apply(implementationArguments, scope)) {
-                    return pair.getRight().apply(implementationArguments, scope);
+            for(Pair<Expression<Boolean>, Block> pair : elseIf) {
+                if(pair.getLeft().evaluate(implementationArguments, scope)) {
+                    return pair.getRight().evaluate(implementationArguments, scope);
                 }
             }
-            if(elseBlock != null) return elseBlock.apply(implementationArguments, scope);
+            if(elseBlock != null) return elseBlock.evaluate(implementationArguments, scope);
         }
-        return new Block.ReturnInfo<>(Block.ReturnLevel.NONE, null);
+        return new Block.EvaluationInfo<>(EvaluationLevel.NONE, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/keywords/looplike/WhileKeyword.java

@@ -7,37 +7,39 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.keywords.looplike;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.Block;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationInfo;
+import com.dfsek.terra.addons.terrascript.parser.lang.Block.EvaluationLevel;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Keyword;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
-public class WhileKeyword implements Keyword<Block.ReturnInfo<?>> {
+public class WhileKeyword implements Keyword<EvaluationInfo<?>> {
     private final Block conditional;
-    private final Returnable<Boolean> statement;
-    private final Position position;
+    private final Expression<Boolean> statement;
+    private final SourcePosition position;
     
-    public WhileKeyword(Block conditional, Returnable<Boolean> statement, Position position) {
+    public WhileKeyword(Block conditional, Expression<Boolean> statement, SourcePosition position) {
         this.conditional = conditional;
         this.statement = statement;
         this.position = position;
     }
     
     @Override
-    public Block.ReturnInfo<?> apply(ImplementationArguments implementationArguments, Scope scope) {
-        while(statement.apply(implementationArguments, scope)) {
-            Block.ReturnInfo<?> level = conditional.apply(implementationArguments, scope);
-            if(level.getLevel().equals(Block.ReturnLevel.BREAK)) break;
-            if(level.getLevel().isReturnFast()) return level;
+    public EvaluationInfo<?> evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        while(statement.evaluate(implementationArguments, scope)) {
+            EvaluationInfo<?> level = conditional.evaluate(implementationArguments, scope);
+            if(level.level().equals(EvaluationLevel.BREAK)) break;
+            if(level.level().isReturnFast()) return level;
         }
-        return new Block.ReturnInfo<>(Block.ReturnLevel.NONE, null);
+        return new EvaluationInfo<>(EvaluationLevel.NONE, null);
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/BinaryOperation.java

@@ -7,23 +7,23 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
-public abstract class BinaryOperation<I, O> implements Returnable<O> {
-    protected final Returnable<I> left;
-    protected final Returnable<I> right;
-    private final Position start;
+public abstract class BinaryOperation<I, O> implements Expression<O> {
+    protected final Expression<I> left;
+    protected final Expression<I> right;
+    private final SourcePosition start;
     
-    public BinaryOperation(Returnable<I> left, Returnable<I> right, Position start) {
+    public BinaryOperation(Expression<I> left, Expression<I> right, SourcePosition start) {
         this.left = left;
         this.right = right;
         this.start = start;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return start;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/BooleanAndOperation.java

@@ -7,14 +7,14 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BooleanAndOperation extends BinaryOperation<Boolean, Boolean> {
-    public BooleanAndOperation(Returnable<Boolean> left, Returnable<Boolean> right, Position start) {
+    public BooleanAndOperation(Expression<Boolean> left, Expression<Boolean> right, SourcePosition start) {
         super(left, right, start);
     }
     
@@ -24,7 +24,7 @@ public class BooleanAndOperation extends BinaryOperation<Boolean, Boolean> {
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/BooleanNotOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BooleanNotOperation extends UnaryOperation<Boolean> {
-    public BooleanNotOperation(Returnable<Boolean> input, Position position) {
+    public BooleanNotOperation(Expression<Boolean> input, SourcePosition position) {
         super(input, position);
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/BooleanOrOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BooleanOrOperation extends BinaryOperation<Boolean, Boolean> {
-    public BooleanOrOperation(Returnable<Boolean> left, Returnable<Boolean> right, Position start) {
+    public BooleanOrOperation(Expression<Boolean> left, Expression<Boolean> right, SourcePosition start) {
         super(left, right, start);
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
@@ -27,7 +27,7 @@ public class BooleanOrOperation extends BinaryOperation<Boolean, Boolean> {
     public boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyBoolean(implementationArguments, scope) || right.applyBoolean(implementationArguments, scope);
     }
-
+    
     @Override
     public ReturnType returnType() {
         return ReturnType.BOOLEAN;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/ConcatenationOperation.java

@@ -7,14 +7,14 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class ConcatenationOperation extends BinaryOperation<Object, Object> {
-    public ConcatenationOperation(Returnable<Object> left, Returnable<Object> right, Position position) {
+    public ConcatenationOperation(Expression<Object> left, Expression<Object> right, SourcePosition position) {
         super(left, right, position);
     }
     
@@ -30,12 +30,12 @@ public class ConcatenationOperation extends BinaryOperation<Object, Object> {
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.STRING;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.STRING;
     }
     
     @Override
-    public Object apply(ImplementationArguments implementationArguments, Scope scope) {
-        return toString(left.apply(implementationArguments, scope)) + toString(right.apply(implementationArguments, scope));
+    public Object evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        return toString(left.evaluate(implementationArguments, scope)) + toString(right.evaluate(implementationArguments, scope));
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/DivisionOperation.java

@@ -7,24 +7,24 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class DivisionOperation extends BinaryOperation<Number, Number> {
-    public DivisionOperation(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public DivisionOperation(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.NUMBER;
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/ModuloOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class ModuloOperation extends BinaryOperation<Number, Number> {
-    public ModuloOperation(Returnable<Number> left, Returnable<Number> right, Position start) {
+    public ModuloOperation(Expression<Number> left, Expression<Number> right, SourcePosition start) {
         super(left, right, start);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     
@@ -27,7 +27,7 @@ public class ModuloOperation extends BinaryOperation<Number, Number> {
     public double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) % right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
     public ReturnType returnType() {
         return ReturnType.NUMBER;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/MultiplicationOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class MultiplicationOperation extends BinaryOperation<Number, Number> {
-    public MultiplicationOperation(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public MultiplicationOperation(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     
@@ -27,7 +27,7 @@ public class MultiplicationOperation extends BinaryOperation<Number, Number> {
     public double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) * right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
     public ReturnType returnType() {
         return ReturnType.NUMBER;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/NegationOperation.java

@@ -7,14 +7,14 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class NegationOperation extends UnaryOperation<Number> {
-    public NegationOperation(Returnable<Number> input, Position position) {
+    public NegationOperation(Expression<Number> input, SourcePosition position) {
         super(input, position);
     }
     
@@ -24,7 +24,7 @@ public class NegationOperation extends UnaryOperation<Number> {
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/NumberAdditionOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class NumberAdditionOperation extends BinaryOperation<Number, Number> {
-    public NumberAdditionOperation(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public NumberAdditionOperation(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     
@@ -27,7 +27,7 @@ public class NumberAdditionOperation extends BinaryOperation<Number, Number> {
     public double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) + right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
     public ReturnType returnType() {
         return ReturnType.NUMBER;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/SubtractionOperation.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class SubtractionOperation extends BinaryOperation<Number, Number> {
-    public SubtractionOperation(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public SubtractionOperation(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     
@@ -27,7 +27,7 @@ public class SubtractionOperation extends BinaryOperation<Number, Number> {
     public double applyDouble(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) - right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
     public ReturnType returnType() {
         return ReturnType.NUMBER;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/UnaryOperation.java

@@ -7,21 +7,21 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
-public abstract class UnaryOperation<T> implements Returnable<T> {
-    protected final Returnable<T> input;
-    private final Position position;
+public abstract class UnaryOperation<T> implements Expression<T> {
+    protected final Expression<T> input;
+    private final SourcePosition position;
     
-    public UnaryOperation(Returnable<T> input, Position position) {
+    public UnaryOperation(Expression<T> input, SourcePosition position) {
         this.input = input;
         this.position = position;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/EqualsStatement.java

@@ -9,40 +9,40 @@ package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 import static com.dfsek.terra.api.util.MathUtil.EPSILON;
 
 
 public class EqualsStatement extends BinaryOperation<Object, Boolean> {
     
-    public EqualsStatement(Returnable<Object> left, Returnable<Object> right, Position position) {
+    public EqualsStatement(Expression<Object> left, Expression<Object> right, SourcePosition position) {
         super(left, right, position);
     }
     
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
     @Override
     public boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
-        Object leftValue = left.apply(implementationArguments, scope);
-        Object rightValue = right.apply(implementationArguments, scope);
+        Object leftValue = left.evaluate(implementationArguments, scope);
+        Object rightValue = right.evaluate(implementationArguments, scope);
         if(leftValue instanceof Number l && rightValue instanceof Number r) {
             return FastMath.abs(l.doubleValue() - r.doubleValue()) <= EPSILON;
         }
-
+        
         return leftValue.equals(rightValue);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/GreaterOrEqualsThanStatement.java

@@ -7,25 +7,25 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class GreaterOrEqualsThanStatement extends BinaryOperation<Number, Boolean> {
-    public GreaterOrEqualsThanStatement(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public GreaterOrEqualsThanStatement(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/GreaterThanStatement.java

@@ -7,21 +7,21 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class GreaterThanStatement extends BinaryOperation<Number, Boolean> {
-    public GreaterThanStatement(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public GreaterThanStatement(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
@@ -31,7 +31,7 @@ public class GreaterThanStatement extends BinaryOperation<Number, Boolean> {
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/LessThanOrEqualsStatement.java

@@ -7,21 +7,21 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class LessThanOrEqualsStatement extends BinaryOperation<Number, Boolean> {
-    public LessThanOrEqualsStatement(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public LessThanOrEqualsStatement(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
@@ -29,9 +29,9 @@ public class LessThanOrEqualsStatement extends BinaryOperation<Number, Boolean>
     public boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) <= right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/LessThanStatement.java

@@ -7,21 +7,21 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class LessThanStatement extends BinaryOperation<Number, Boolean> {
-    public LessThanStatement(Returnable<Number> left, Returnable<Number> right, Position position) {
+    public LessThanStatement(Expression<Number> left, Expression<Number> right, SourcePosition position) {
         super(left, right, position);
     }
     
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
@@ -29,9 +29,9 @@ public class LessThanStatement extends BinaryOperation<Number, Boolean> {
     public boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
         return left.applyDouble(implementationArguments, scope) < right.applyDouble(implementationArguments, scope);
     }
-
+    
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/operations/statements/NotEqualsStatement.java

@@ -9,29 +9,29 @@ package com.dfsek.terra.addons.terrascript.parser.lang.operations.statements;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.operations.BinaryOperation;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 import static com.dfsek.terra.api.util.MathUtil.EPSILON;
 
 
 public class NotEqualsStatement extends BinaryOperation<Object, Boolean> {
-    public NotEqualsStatement(Returnable<Object> left, Returnable<Object> right, Position position) {
+    public NotEqualsStatement(Expression<Object> left, Expression<Object> right, SourcePosition position) {
         super(left, right, position);
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     
     @Override
     public boolean applyBoolean(ImplementationArguments implementationArguments, Scope scope) {
-        Object leftValue = left.apply(implementationArguments, scope);
-        Object rightValue = right.apply(implementationArguments, scope);
+        Object leftValue = left.evaluate(implementationArguments, scope);
+        Object rightValue = right.evaluate(implementationArguments, scope);
         if(leftValue instanceof Number l && rightValue instanceof Number r) {
             return FastMath.abs(l.doubleValue() - r.doubleValue()) > EPSILON;
         }
@@ -40,7 +40,7 @@ public class NotEqualsStatement extends BinaryOperation<Object, Boolean> {
     }
     
     @Override
-    public Returnable.ReturnType returnType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType returnType() {
+        return Expression.ReturnType.BOOLEAN;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/BooleanVariable.java

@@ -7,15 +7,15 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public class BooleanVariable implements Variable<Boolean> {
-    private final Position position;
+    private final SourcePosition position;
     private Boolean value;
     
-    public BooleanVariable(Boolean value, Position position) {
+    public BooleanVariable(Boolean value, SourcePosition position) {
         this.value = value;
         this.position = position;
     }
@@ -31,12 +31,12 @@ public class BooleanVariable implements Variable<Boolean> {
     }
     
     @Override
-    public Returnable.ReturnType getType() {
-        return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType getType() {
+        return Expression.ReturnType.BOOLEAN;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/NumberVariable.java

@@ -7,15 +7,15 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public class NumberVariable implements Variable<Number> {
-    private final Position position;
+    private final SourcePosition position;
     private Number value;
     
-    public NumberVariable(Number value, Position position) {
+    public NumberVariable(Number value, SourcePosition position) {
         this.value = value;
         this.position = position;
     }
@@ -31,12 +31,12 @@ public class NumberVariable implements Variable<Number> {
     }
     
     @Override
-    public Returnable.ReturnType getType() {
-        return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType getType() {
+        return Expression.ReturnType.NUMBER;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/StringVariable.java

@@ -7,15 +7,15 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public class StringVariable implements Variable<String> {
-    private final Position position;
+    private final SourcePosition position;
     private String value;
     
-    public StringVariable(String value, Position position) {
+    public StringVariable(String value, SourcePosition position) {
         this.value = value;
         this.position = position;
     }
@@ -31,12 +31,12 @@ public class StringVariable implements Variable<String> {
     }
     
     @Override
-    public Returnable.ReturnType getType() {
-        return Returnable.ReturnType.STRING;
+    public Expression.ReturnType getType() {
+        return Expression.ReturnType.STRING;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/Variable.java

@@ -7,8 +7,8 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
 public interface Variable<T> {
@@ -16,7 +16,7 @@ public interface Variable<T> {
     
     void setValue(T value);
     
-    Returnable.ReturnType getType();
+    Expression.ReturnType getType();
     
-    Position getPosition();
+    SourcePosition getPosition();
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/assign/BoolAssignmentNode.java

@@ -1,18 +1,23 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.assign;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BoolAssignmentNode extends VariableAssignmentNode<Boolean> {
-    public BoolAssignmentNode(Returnable<Boolean> value, Position position, int index) {
+    public BoolAssignmentNode(Expression<Boolean> value, SourcePosition position, int index) {
         super(value, position, index);
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public ReturnType returnType() {
+        return ReturnType.BOOLEAN;
+    }
+    
+    @Override
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyBoolean(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/assign/NumAssignmentNode.java

@@ -1,18 +1,23 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.assign;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class NumAssignmentNode extends VariableAssignmentNode<Number> {
-    public NumAssignmentNode(Returnable<Number> value, Position position, int index) {
+    public NumAssignmentNode(Expression<Number> value, SourcePosition position, int index) {
         super(value, position, index);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public ReturnType returnType() {
+        return ReturnType.NUMBER;
+    }
+    
+    @Override
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return applyDouble(implementationArguments, scope);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/assign/StrAssignmentNode.java

@@ -1,19 +1,24 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.assign;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class StrAssignmentNode extends VariableAssignmentNode<String> {
-    public StrAssignmentNode(Returnable<String> value, Position position, int index) {
+    public StrAssignmentNode(Expression<String> value, SourcePosition position, int index) {
         super(value, position, index);
     }
     
     @Override
-    public String apply(ImplementationArguments implementationArguments, Scope scope) {
-        String val = value.apply(implementationArguments, scope);
+    public ReturnType returnType() {
+        return ReturnType.STRING;
+    }
+    
+    @Override
+    public String evaluate(ImplementationArguments implementationArguments, Scope scope) {
+        String val = value.evaluate(implementationArguments, scope);
         scope.setStr(index, val);
         return val;
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/assign/VariableAssignmentNode.java

@@ -7,25 +7,24 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.assign;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Item;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
-public abstract class VariableAssignmentNode<T> implements Item<T> {
-    protected final Returnable<T> value;
+public abstract class VariableAssignmentNode<T> implements Expression<T> {
+    protected final Expression<T> value;
     protected final int index;
-    private final Position position;
+    private final SourcePosition position;
     
     
-    public VariableAssignmentNode(Returnable<T> value, Position position, int index) {
+    public VariableAssignmentNode(Expression<T> value, SourcePosition position, int index) {
         this.value = value;
         this.index = index;
         this.position = position;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/reference/BoolVariableReferenceNode.java

@@ -1,17 +1,17 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.reference;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BoolVariableReferenceNode extends VariableReferenceNode<Boolean> {
-    public BoolVariableReferenceNode(Position position, ReturnType type, int index) {
+    public BoolVariableReferenceNode(SourcePosition position, ReturnType type, int index) {
         super(position, type, index);
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return scope.getBool(index);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/reference/NumVariableReferenceNode.java

@@ -1,17 +1,17 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.reference;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class NumVariableReferenceNode extends VariableReferenceNode<Number> {
-    public NumVariableReferenceNode(Position position, ReturnType type, int index) {
+    public NumVariableReferenceNode(SourcePosition position, ReturnType type, int index) {
         super(position, type, index);
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return scope.getNum(index);
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/reference/StrVariableReferenceNode.java

@@ -1,17 +1,17 @@
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.reference;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class StrVariableReferenceNode extends VariableReferenceNode<String> {
-    public StrVariableReferenceNode(Position position, ReturnType type, int index) {
+    public StrVariableReferenceNode(SourcePosition position, ReturnType type, int index) {
         super(position, type, index);
     }
     
     @Override
-    public String apply(ImplementationArguments implementationArguments, Scope scope) {
+    public String evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return scope.getStr(index);
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/parser/lang/variables/reference/VariableReferenceNode.java

@@ -7,16 +7,16 @@
 
 package com.dfsek.terra.addons.terrascript.parser.lang.variables.reference;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 
 
-public abstract class VariableReferenceNode<T> implements Returnable<T> {
+public abstract class VariableReferenceNode<T> implements Expression<T> {
     protected final int index;
-    private final Position position;
+    private final SourcePosition position;
     private final ReturnType type;
     
-    public VariableReferenceNode(Position position, ReturnType type, int index) {
+    public VariableReferenceNode(SourcePosition position, ReturnType type, int index) {
         this.position = position;
         this.type = type;
         this.index = index;
@@ -28,7 +28,7 @@ public abstract class VariableReferenceNode<T> implements Returnable<T> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/StructureScript.java

@@ -7,6 +7,8 @@
 
 package com.dfsek.terra.addons.terrascript.script;
 
+import com.dfsek.terra.addons.terrascript.lexer.Lexer;
+
 import net.jafama.FastMath;
 import org.apache.commons.io.IOUtils;
 import org.slf4j.Logger;
@@ -19,7 +21,8 @@ import java.util.Random;
 
 import com.dfsek.terra.addons.terrascript.parser.Parser;
 import com.dfsek.terra.addons.terrascript.parser.lang.Executable;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
+import com.dfsek.terra.addons.terrascript.parser.lang.Scope.ScopeBuilder;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.builders.BinaryNumberFunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.builders.BiomeFunctionBuilder;
@@ -51,32 +54,34 @@ import com.dfsek.terra.api.world.WritableWorld;
 
 public class StructureScript implements Structure, Keyed<StructureScript> {
     private static final Logger LOGGER = LoggerFactory.getLogger(StructureScript.class);
-    private final Executable block;
+    private final Executable executable;
     private final RegistryKey id;
     
     private final String profile;
     private final Platform platform;
     
     @SuppressWarnings("rawtypes")
-    public StructureScript(InputStream inputStream, RegistryKey id, Platform platform, Registry<Structure> registry,
+    public StructureScript(InputStream source, RegistryKey id, Platform platform, Registry<Structure> structureRegistry,
                            Registry<LootTable> lootRegistry,
                            Registry<FunctionBuilder> functionRegistry) {
-        Parser parser;
+        Lexer lexer;
         try {
-            parser = new Parser(IOUtils.toString(inputStream, Charset.defaultCharset()));
+            lexer = new Lexer(IOUtils.toString(source, Charset.defaultCharset()));
         } catch(IOException e) {
             throw new RuntimeException(e);
         }
+        Parser parser = new Parser(lexer);
         this.id = id;
         this.profile = "terrascript_direct:" + id;
         
-        //noinspection unchecked
-        functionRegistry.forEach((key, function) -> parser.registerFunction(key.getID(), function)); // Register registry functions.
+        ScopeBuilder scope = new ScopeBuilder();
         
-        parser
+        functionRegistry.forEach((key, function) -> scope.registerFunction(key.getID(), function)); // Register registry functions.
+        
+        scope
                 .registerFunction("block", new BlockFunctionBuilder(platform))
                 .registerFunction("debugBlock", new BlockFunctionBuilder(platform))
-                .registerFunction("structure", new StructureFunctionBuilder(registry, platform))
+                .registerFunction("structure", new StructureFunctionBuilder(structureRegistry, platform))
                 .registerFunction("randomInt", new RandomFunctionBuilder())
                 .registerFunction("recursions", new RecursionsFunctionBuilder())
                 .registerFunction("setMark", new SetMarkFunctionBuilder())
@@ -89,15 +94,15 @@ public class StructureScript implements Structure, Keyed<StructureScript> {
                 .registerFunction("state", new StateFunctionBuilder(platform))
                 .registerFunction("setWaterlog", new UnaryBooleanFunctionBuilder((waterlog, args) -> args.setWaterlog(waterlog)))
                 .registerFunction("originX", new ZeroArgFunctionBuilder<Number>(arguments -> arguments.getOrigin().getX(),
-                                                                                Returnable.ReturnType.NUMBER))
+                                                                                Expression.ReturnType.NUMBER))
                 .registerFunction("originY", new ZeroArgFunctionBuilder<Number>(arguments -> arguments.getOrigin().getY(),
-                                                                                Returnable.ReturnType.NUMBER))
+                                                                                Expression.ReturnType.NUMBER))
                 .registerFunction("originZ", new ZeroArgFunctionBuilder<Number>(arguments -> arguments.getOrigin().getZ(),
-                                                                                Returnable.ReturnType.NUMBER))
+                                                                                Expression.ReturnType.NUMBER))
                 .registerFunction("rotation", new ZeroArgFunctionBuilder<>(arguments -> arguments.getRotation().toString(),
-                                                                           Returnable.ReturnType.STRING))
+                                                                           Expression.ReturnType.STRING))
                 .registerFunction("rotationDegrees", new ZeroArgFunctionBuilder<>(arguments -> arguments.getRotation().getDegrees(),
-                                                                                  Returnable.ReturnType.NUMBER))
+                                                                                  Expression.ReturnType.NUMBER))
                 .registerFunction("print",
                                   new UnaryStringFunctionBuilder(string -> LOGGER.info("[TerraScript:{}] {}", id, string)))
                 .registerFunction("abs", new UnaryNumberFunctionBuilder(number -> FastMath.abs(number.doubleValue())))
@@ -120,11 +125,7 @@ public class StructureScript implements Structure, Keyed<StructureScript> {
                 .registerFunction("min", new BinaryNumberFunctionBuilder(
                         (number, number2) -> FastMath.min(number.doubleValue(), number2.doubleValue())));
         
-        if(!platform.getTerraConfig().isDebugScript()) {
-            parser.ignoreFunction("debugBlock");
-        }
-        
-        block = parser.parse();
+        executable = parser.parse(scope);
         this.platform = platform;
     }
     
@@ -132,21 +133,21 @@ public class StructureScript implements Structure, Keyed<StructureScript> {
     @SuppressWarnings("try")
     public boolean generate(Vector3Int location, WritableWorld world, Random random, Rotation rotation) {
         platform.getProfiler().push(profile);
-        boolean result = applyBlock(new TerraImplementationArguments(location, rotation, random, world, 0));
+        boolean result = execute(new TerraImplementationArguments(location, rotation, random, world, 0));
         platform.getProfiler().pop(profile);
         return result;
     }
     
     public boolean generate(Vector3Int location, WritableWorld world, Random random, Rotation rotation, int recursions) {
         platform.getProfiler().push(profile);
-        boolean result = applyBlock(new TerraImplementationArguments(location, rotation, random, world, recursions));
+        boolean result = execute(new TerraImplementationArguments(location, rotation, random, world, recursions));
         platform.getProfiler().pop(profile);
         return result;
     }
     
-    private boolean applyBlock(TerraImplementationArguments arguments) {
+    private boolean execute(TerraImplementationArguments arguments) {
         try {
-            return block.execute(arguments);
+            return executable.execute(arguments);
         } catch(RuntimeException e) {
             LOGGER.error("Failed to generate structure at {}", arguments.getOrigin(), e);
             return false;

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/BinaryNumberFunctionBuilder.java

@@ -10,12 +10,12 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 import java.util.List;
 import java.util.function.BiFunction;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class BinaryNumberFunctionBuilder implements FunctionBuilder<Function<Number>> {
@@ -27,7 +27,7 @@ public class BinaryNumberFunctionBuilder implements FunctionBuilder<Function<Num
     }
     
     @Override
-    public Function<Number> build(List<Returnable<?>> argumentList, Position position) {
+    public Function<Number> build(List<Expression<?>> argumentList, SourcePosition position) {
         return new Function<>() {
             @Override
             public ReturnType returnType() {
@@ -36,13 +36,13 @@ public class BinaryNumberFunctionBuilder implements FunctionBuilder<Function<Num
             
             @SuppressWarnings("unchecked")
             @Override
-            public Number apply(ImplementationArguments implementationArguments, Scope scope) {
-                return function.apply(((Returnable<Number>) argumentList.get(0)).apply(implementationArguments, scope),
-                                      ((Returnable<Number>) argumentList.get(1)).apply(implementationArguments, scope));
+            public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
+                return function.apply(((Expression<Number>) argumentList.get(0)).evaluate(implementationArguments, scope),
+                                      ((Expression<Number>) argumentList.get(1)).evaluate(implementationArguments, scope));
             }
             
             @Override
-            public Position getPosition() {
+            public SourcePosition getPosition() {
                 return position;
             }
         };
@@ -54,8 +54,8 @@ public class BinaryNumberFunctionBuilder implements FunctionBuilder<Function<Num
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
-        if(position == 0 || position == 1) return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType getArgument(int position) {
+        if(position == 0 || position == 1) return Expression.ReturnType.NUMBER;
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/BiomeFunctionBuilder.java

@@ -9,10 +9,10 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.BiomeFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 
 
@@ -25,9 +25,9 @@ public class BiomeFunctionBuilder implements FunctionBuilder<BiomeFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public BiomeFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new BiomeFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                 (Returnable<Number>) argumentList.get(2), position);
+    public BiomeFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new BiomeFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                 (Expression<Number>) argumentList.get(2), position);
     }
     
     @Override
@@ -36,9 +36,9 @@ public class BiomeFunctionBuilder implements FunctionBuilder<BiomeFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/BlockFunctionBuilder.java

@@ -9,13 +9,13 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.BooleanConstant;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.StringConstant;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.BlockFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 
 
@@ -28,17 +28,17 @@ public class BlockFunctionBuilder implements FunctionBuilder<BlockFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public BlockFunction build(List<Returnable<?>> argumentList, Position position) {
+    public BlockFunction build(List<Expression<?>> argumentList, SourcePosition position) {
         if(argumentList.size() < 4) throw new ParseException("Expected data", position);
-        Returnable<Boolean> booleanReturnable = new BooleanConstant(true, position);
-        if(argumentList.size() == 5) booleanReturnable = (Returnable<Boolean>) argumentList.get(4);
+        Expression<Boolean> booleanReturnable = new BooleanConstant(true, position);
+        if(argumentList.size() == 5) booleanReturnable = (Expression<Boolean>) argumentList.get(4);
         if(argumentList.get(3) instanceof StringConstant) {
-            return new BlockFunction.Constant((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                              (Returnable<Number>) argumentList.get(2), (StringConstant) argumentList.get(3),
+            return new BlockFunction.Constant((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                              (Expression<Number>) argumentList.get(2), (StringConstant) argumentList.get(3),
                                               booleanReturnable, platform, position);
         }
-        return new BlockFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                 (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), booleanReturnable,
+        return new BlockFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                 (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), booleanReturnable,
                                  platform, position);
     }
     
@@ -48,11 +48,11 @@ public class BlockFunctionBuilder implements FunctionBuilder<BlockFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
-            case 4 -> Returnable.ReturnType.BOOLEAN;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
+            case 4 -> Expression.ReturnType.BOOLEAN;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/CheckBlockFunctionBuilder.java

@@ -9,18 +9,18 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.CheckBlockFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class CheckBlockFunctionBuilder implements FunctionBuilder<CheckBlockFunction> {
     @SuppressWarnings("unchecked")
     @Override
-    public CheckBlockFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new CheckBlockFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                      (Returnable<Number>) argumentList.get(2), position);
+    public CheckBlockFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new CheckBlockFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                      (Expression<Number>) argumentList.get(2), position);
     }
     
     @Override
@@ -29,9 +29,9 @@ public class CheckBlockFunctionBuilder implements FunctionBuilder<CheckBlockFunc
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/EntityFunctionBuilder.java

@@ -9,10 +9,10 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.EntityFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 
 
@@ -25,9 +25,9 @@ public class EntityFunctionBuilder implements FunctionBuilder<EntityFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public EntityFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new EntityFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                  (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), platform, position);
+    public EntityFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new EntityFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                  (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), platform, position);
     }
     
     @Override
@@ -36,10 +36,10 @@ public class EntityFunctionBuilder implements FunctionBuilder<EntityFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/GetMarkFunctionBuilder.java

@@ -9,10 +9,10 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.GetMarkFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class GetMarkFunctionBuilder implements FunctionBuilder<GetMarkFunction> {
@@ -22,9 +22,9 @@ public class GetMarkFunctionBuilder implements FunctionBuilder<GetMarkFunction>
     
     @SuppressWarnings("unchecked")
     @Override
-    public GetMarkFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new GetMarkFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                   (Returnable<Number>) argumentList.get(2), position);
+    public GetMarkFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new GetMarkFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                   (Expression<Number>) argumentList.get(2), position);
     }
     
     @Override
@@ -33,9 +33,9 @@ public class GetMarkFunctionBuilder implements FunctionBuilder<GetMarkFunction>
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/LootFunctionBuilder.java

@@ -9,11 +9,11 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.StructureScript;
 import com.dfsek.terra.addons.terrascript.script.functions.LootFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.registry.Registry;
 import com.dfsek.terra.api.structure.LootTable;
@@ -32,9 +32,9 @@ public class LootFunctionBuilder implements FunctionBuilder<LootFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public LootFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new LootFunction(registry, (Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), platform, position,
+    public LootFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new LootFunction(registry, (Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), platform, position,
                                 script);
     }
     
@@ -44,10 +44,10 @@ public class LootFunctionBuilder implements FunctionBuilder<LootFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/PullFunctionBuilder.java

@@ -9,10 +9,10 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.PullFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 
 
@@ -25,9 +25,9 @@ public class PullFunctionBuilder implements FunctionBuilder<PullFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public PullFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new PullFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), platform, position);
+    public PullFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new PullFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), platform, position);
     }
     
     @Override
@@ -36,10 +36,10 @@ public class PullFunctionBuilder implements FunctionBuilder<PullFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/RandomFunctionBuilder.java

@@ -9,17 +9,17 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.RandomFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class RandomFunctionBuilder implements FunctionBuilder<RandomFunction> {
     @SuppressWarnings("unchecked")
     @Override
-    public RandomFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new RandomFunction((Returnable<Number>) argumentList.get(0), position);
+    public RandomFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new RandomFunction((Expression<Number>) argumentList.get(0), position);
     }
     
     @Override
@@ -28,8 +28,8 @@ public class RandomFunctionBuilder implements FunctionBuilder<RandomFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
-        if(position == 0) return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType getArgument(int position) {
+        if(position == 0) return Expression.ReturnType.NUMBER;
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/RecursionsFunctionBuilder.java

@@ -9,15 +9,15 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.RecursionsFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class RecursionsFunctionBuilder implements FunctionBuilder<RecursionsFunction> {
     @Override
-    public RecursionsFunction build(List<Returnable<?>> argumentList, Position position) {
+    public RecursionsFunction build(List<Expression<?>> argumentList, SourcePosition position) {
         return new RecursionsFunction(position);
     }
     
@@ -27,7 +27,7 @@ public class RecursionsFunctionBuilder implements FunctionBuilder<RecursionsFunc
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/SetMarkFunctionBuilder.java

@@ -9,10 +9,10 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.SetMarkFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class SetMarkFunctionBuilder implements FunctionBuilder<SetMarkFunction> {
@@ -22,9 +22,9 @@ public class SetMarkFunctionBuilder implements FunctionBuilder<SetMarkFunction>
     
     @SuppressWarnings("unchecked")
     @Override
-    public SetMarkFunction build(List<Returnable<?>> argumentList, Position position) {
-        return new SetMarkFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                   (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), position);
+    public SetMarkFunction build(List<Expression<?>> argumentList, SourcePosition position) {
+        return new SetMarkFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                   (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), position);
     }
     
     @Override
@@ -33,10 +33,10 @@ public class SetMarkFunctionBuilder implements FunctionBuilder<SetMarkFunction>
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/StateFunctionBuilder.java

@@ -9,11 +9,11 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.StateFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 
 
@@ -26,10 +26,10 @@ public class StateFunctionBuilder implements FunctionBuilder<StateFunction> {
     
     @SuppressWarnings("unchecked")
     @Override
-    public StateFunction build(List<Returnable<?>> argumentList, Position position) {
+    public StateFunction build(List<Expression<?>> argumentList, SourcePosition position) {
         if(argumentList.size() < 4) throw new ParseException("Expected data", position);
-        return new StateFunction((Returnable<Number>) argumentList.get(0), (Returnable<Number>) argumentList.get(1),
-                                 (Returnable<Number>) argumentList.get(2), (Returnable<String>) argumentList.get(3), position);
+        return new StateFunction((Expression<Number>) argumentList.get(0), (Expression<Number>) argumentList.get(1),
+                                 (Expression<Number>) argumentList.get(2), (Expression<String>) argumentList.get(3), position);
     }
     
     @Override
@@ -38,10 +38,10 @@ public class StateFunctionBuilder implements FunctionBuilder<StateFunction> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            case 3 -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            case 3 -> Expression.ReturnType.STRING;
             default -> null;
         };
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/StructureFunctionBuilder.java

@@ -10,11 +10,11 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 import java.util.List;
 import java.util.stream.Collectors;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.functions.StructureFunction;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.registry.Registry;
 import com.dfsek.terra.api.structure.Structure;
@@ -31,12 +31,12 @@ public class StructureFunctionBuilder implements FunctionBuilder<StructureFuncti
     
     @SuppressWarnings("unchecked")
     @Override
-    public StructureFunction build(List<Returnable<?>> argumentList, Position position) {
+    public StructureFunction build(List<Expression<?>> argumentList, SourcePosition position) {
         if(argumentList.size() < 5) throw new ParseException("Expected rotations", position);
         
-        return new StructureFunction((Returnable<Number>) argumentList.remove(0), (Returnable<Number>) argumentList.remove(0),
-                                     (Returnable<Number>) argumentList.remove(0), (Returnable<String>) argumentList.remove(0),
-                                     argumentList.stream().map(item -> ((Returnable<String>) item)).collect(Collectors.toList()), registry,
+        return new StructureFunction((Expression<Number>) argumentList.remove(0), (Expression<Number>) argumentList.remove(0),
+                                     (Expression<Number>) argumentList.remove(0), (Expression<String>) argumentList.remove(0),
+                                     argumentList.stream().map(item -> ((Expression<String>) item)).collect(Collectors.toList()), registry,
                                      position, platform);
     }
     
@@ -46,10 +46,10 @@ public class StructureFunctionBuilder implements FunctionBuilder<StructureFuncti
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         return switch(position) {
-            case 0, 1, 2 -> Returnable.ReturnType.NUMBER;
-            default -> Returnable.ReturnType.STRING;
+            case 0, 1, 2 -> Expression.ReturnType.NUMBER;
+            default -> Expression.ReturnType.STRING;
         };
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/UnaryBooleanFunctionBuilder.java

@@ -10,13 +10,13 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 import java.util.List;
 import java.util.function.BiConsumer;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class UnaryBooleanFunctionBuilder implements FunctionBuilder<Function<Void>> {
@@ -28,7 +28,7 @@ public class UnaryBooleanFunctionBuilder implements FunctionBuilder<Function<Voi
     }
     
     @Override
-    public Function<Void> build(List<Returnable<?>> argumentList, Position position) {
+    public Function<Void> build(List<Expression<?>> argumentList, SourcePosition position) {
         return new Function<>() {
             @Override
             public ReturnType returnType() {
@@ -37,14 +37,14 @@ public class UnaryBooleanFunctionBuilder implements FunctionBuilder<Function<Voi
             
             @SuppressWarnings("unchecked")
             @Override
-            public Void apply(ImplementationArguments implementationArguments, Scope scope) {
-                function.accept(((Returnable<Boolean>) argumentList.get(0)).apply(implementationArguments, scope),
+            public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
+                function.accept(((Expression<Boolean>) argumentList.get(0)).evaluate(implementationArguments, scope),
                                 (TerraImplementationArguments) implementationArguments);
                 return null;
             }
             
             @Override
-            public Position getPosition() {
+            public SourcePosition getPosition() {
                 return position;
             }
         };
@@ -56,8 +56,8 @@ public class UnaryBooleanFunctionBuilder implements FunctionBuilder<Function<Voi
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
-        if(position == 0) return Returnable.ReturnType.BOOLEAN;
+    public Expression.ReturnType getArgument(int position) {
+        if(position == 0) return Expression.ReturnType.BOOLEAN;
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/UnaryNumberFunctionBuilder.java

@@ -9,12 +9,12 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class UnaryNumberFunctionBuilder implements FunctionBuilder<Function<Number>> {
@@ -26,7 +26,7 @@ public class UnaryNumberFunctionBuilder implements FunctionBuilder<Function<Numb
     }
     
     @Override
-    public Function<Number> build(List<Returnable<?>> argumentList, Position position) {
+    public Function<Number> build(List<Expression<?>> argumentList, SourcePosition position) {
         return new Function<>() {
             @Override
             public ReturnType returnType() {
@@ -35,12 +35,12 @@ public class UnaryNumberFunctionBuilder implements FunctionBuilder<Function<Numb
             
             @SuppressWarnings("unchecked")
             @Override
-            public Number apply(ImplementationArguments implementationArguments, Scope scope) {
-                return function.apply(((Returnable<Number>) argumentList.get(0)).apply(implementationArguments, scope));
+            public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
+                return function.apply(((Expression<Number>) argumentList.get(0)).evaluate(implementationArguments, scope));
             }
             
             @Override
-            public Position getPosition() {
+            public SourcePosition getPosition() {
                 return position;
             }
         };
@@ -52,8 +52,8 @@ public class UnaryNumberFunctionBuilder implements FunctionBuilder<Function<Numb
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
-        if(position == 0) return Returnable.ReturnType.NUMBER;
+    public Expression.ReturnType getArgument(int position) {
+        if(position == 0) return Expression.ReturnType.NUMBER;
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/UnaryStringFunctionBuilder.java

@@ -9,12 +9,12 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class UnaryStringFunctionBuilder implements FunctionBuilder<Function<Void>> {
@@ -26,7 +26,7 @@ public class UnaryStringFunctionBuilder implements FunctionBuilder<Function<Void
     }
     
     @Override
-    public Function<Void> build(List<Returnable<?>> argumentList, Position position) {
+    public Function<Void> build(List<Expression<?>> argumentList, SourcePosition position) {
         return new Function<>() {
             @Override
             public ReturnType returnType() {
@@ -35,13 +35,13 @@ public class UnaryStringFunctionBuilder implements FunctionBuilder<Function<Void
             
             @SuppressWarnings("unchecked")
             @Override
-            public Void apply(ImplementationArguments implementationArguments, Scope scope) {
-                function.accept(((Returnable<String>) argumentList.get(0)).apply(implementationArguments, scope));
+            public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
+                function.accept(((Expression<String>) argumentList.get(0)).evaluate(implementationArguments, scope));
                 return null;
             }
             
             @Override
-            public Position getPosition() {
+            public SourcePosition getPosition() {
                 return position;
             }
         };
@@ -53,8 +53,8 @@ public class UnaryStringFunctionBuilder implements FunctionBuilder<Function<Void
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
-        if(position == 0) return Returnable.ReturnType.STRING;
+    public Expression.ReturnType getArgument(int position) {
+        if(position == 0) return Expression.ReturnType.STRING;
         return null;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/builders/ZeroArgFunctionBuilder.java

@@ -9,26 +9,26 @@ package com.dfsek.terra.addons.terrascript.script.builders;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.FunctionBuilder;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class ZeroArgFunctionBuilder<T> implements FunctionBuilder<Function<T>> {
     private final java.util.function.Function<TerraImplementationArguments, T> function;
-    private final Returnable.ReturnType type;
+    private final Expression.ReturnType type;
     
-    public ZeroArgFunctionBuilder(java.util.function.Function<TerraImplementationArguments, T> function, Returnable.ReturnType type) {
+    public ZeroArgFunctionBuilder(java.util.function.Function<TerraImplementationArguments, T> function, Expression.ReturnType type) {
         this.function = function;
         this.type = type;
     }
     
     @Override
-    public Function<T> build(List<Returnable<?>> argumentList, Position position) {
+    public Function<T> build(List<Expression<?>> argumentList, SourcePosition position) {
         return new Function<>() {
             @Override
             public ReturnType returnType() {
@@ -36,12 +36,12 @@ public class ZeroArgFunctionBuilder<T> implements FunctionBuilder<Function<T>> {
             }
             
             @Override
-            public T apply(ImplementationArguments implementationArguments, Scope scope) {
+            public T evaluate(ImplementationArguments implementationArguments, Scope scope) {
                 return function.apply((TerraImplementationArguments) implementationArguments);
             }
             
             @Override
-            public Position getPosition() {
+            public SourcePosition getPosition() {
                 return position;
             }
         };
@@ -53,7 +53,7 @@ public class ZeroArgFunctionBuilder<T> implements FunctionBuilder<Function<T>> {
     }
     
     @Override
-    public Returnable.ReturnType getArgument(int position) {
+    public Expression.ReturnType getArgument(int position) {
         if(position == 0) return type;
         return null;
     }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/BiomeFunction.java

@@ -9,12 +9,12 @@ package com.dfsek.terra.addons.terrascript.script.functions;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.util.RotationUtil;
 import com.dfsek.terra.api.util.vector.Vector2;
 import com.dfsek.terra.api.util.vector.Vector3;
@@ -22,11 +22,11 @@ import com.dfsek.terra.api.world.biome.generation.BiomeProvider;
 
 
 public class BiomeFunction implements Function<String> {
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     
     
-    public BiomeFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Position position) {
+    public BiomeFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, SourcePosition position) {
         this.x = x;
         this.y = y;
         this.z = z;
@@ -35,11 +35,11 @@ public class BiomeFunction implements Function<String> {
     
     
     @Override
-    public String apply(ImplementationArguments implementationArguments, Scope scope) {
+    public String evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
         
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()),
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
                                                arguments.getRotation());
         
         
@@ -49,12 +49,12 @@ public class BiomeFunction implements Function<String> {
                                       .toVector3()
                                       .mutable()
                                       .add(Vector3.of(FastMath.roundToInt(xz.getX()),
-                                                      y.apply(implementationArguments, scope).intValue(),
+                                                      y.evaluate(implementationArguments, scope).intValue(),
                                                       FastMath.roundToInt(xz.getZ()))).immutable(), arguments.getWorld().getSeed()).getID();
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/BlockFunction.java

@@ -14,13 +14,13 @@ import org.slf4j.LoggerFactory;
 import java.util.HashMap;
 import java.util.Map;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.StringConstant;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.block.state.BlockState;
 import com.dfsek.terra.api.util.RotationUtil;
@@ -30,15 +30,15 @@ import com.dfsek.terra.api.util.vector.Vector3;
 
 public class BlockFunction implements Function<Void> {
     private static final Logger logger = LoggerFactory.getLogger(BlockFunction.class);
-    protected final Returnable<Number> x, y, z;
-    protected final Returnable<String> blockData;
+    protected final Expression<Number> x, y, z;
+    protected final Expression<String> blockData;
     protected final Platform platform;
     private final Map<String, BlockState> data = new HashMap<>();
-    private final Returnable<Boolean> overwrite;
-    private final Position position;
+    private final Expression<Boolean> overwrite;
+    private final SourcePosition position;
     
-    public BlockFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> blockData,
-                         Returnable<Boolean> overwrite, Platform platform, Position position) {
+    public BlockFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> blockData,
+                         Expression<Boolean> overwrite, Platform platform, SourcePosition position) {
         this.x = x;
         this.y = y;
         this.z = z;
@@ -49,7 +49,7 @@ public class BlockFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
         BlockState rot = getBlockState(implementationArguments, scope);
         setBlock(implementationArguments, scope, arguments, rot);
@@ -57,7 +57,7 @@ public class BlockFunction implements Function<Void> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     
@@ -68,14 +68,15 @@ public class BlockFunction implements Function<Void> {
     
     void setBlock(ImplementationArguments implementationArguments, Scope scope,
                   TerraImplementationArguments arguments, BlockState rot) {
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         try {
             Vector3.Mutable set = Vector3.of(FastMath.roundToInt(xz.getX()),
-                                             y.apply(implementationArguments, scope).doubleValue(),
+                                             y.evaluate(implementationArguments, scope).doubleValue(),
                                              FastMath.roundToInt(xz.getZ())).mutable().add(arguments.getOrigin());
             BlockState current = arguments.getWorld().getBlockState(set);
-            if(overwrite.apply(implementationArguments, scope) || current.isAir()) {
+            if(overwrite.evaluate(implementationArguments, scope) || current.isAir()) {
                 arguments.getWorld().setBlockState(set, rot);
             }
         } catch(RuntimeException e) {
@@ -84,15 +85,15 @@ public class BlockFunction implements Function<Void> {
     }
     
     protected BlockState getBlockState(ImplementationArguments arguments, Scope scope) {
-        return data.computeIfAbsent(blockData.apply(arguments, scope), platform.getWorldHandle()::createBlockState);
+        return data.computeIfAbsent(blockData.evaluate(arguments, scope), platform.getWorldHandle()::createBlockState);
     }
     
     
     public static class Constant extends BlockFunction {
         private final BlockState state;
         
-        public Constant(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, StringConstant blockData,
-                        Returnable<Boolean> overwrite, Platform platform, Position position) {
+        public Constant(Expression<Number> x, Expression<Number> y, Expression<Number> z, StringConstant blockData,
+                        Expression<Boolean> overwrite, Platform platform, SourcePosition position) {
             super(x, y, z, blockData, overwrite, platform, position);
             this.state = platform.getWorldHandle().createBlockState(blockData.getConstant());
         }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/CheckBlockFunction.java

@@ -9,22 +9,22 @@ package com.dfsek.terra.addons.terrascript.script.functions;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.util.RotationUtil;
 import com.dfsek.terra.api.util.vector.Vector2;
 import com.dfsek.terra.api.util.vector.Vector3;
 
 
 public class CheckBlockFunction implements Function<String> {
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     
-    public CheckBlockFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Position position) {
+    public CheckBlockFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, SourcePosition position) {
         this.x = x;
         this.y = y;
         this.z = z;
@@ -33,11 +33,11 @@ public class CheckBlockFunction implements Function<String> {
     
     
     @Override
-    public String apply(ImplementationArguments implementationArguments, Scope scope) {
+    public String evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
         
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()),
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
                                                arguments.getRotation());
         
         
@@ -46,7 +46,7 @@ public class CheckBlockFunction implements Function<String> {
                                                        .toVector3()
                                                        .mutable()
                                                        .add(Vector3.of(FastMath.roundToInt(xz.getX()),
-                                                                       y.apply(implementationArguments, scope)
+                                                                       y.evaluate(implementationArguments, scope)
                                                                         .doubleValue(), FastMath.roundToInt(xz.getZ()))))
                                .getAsString();
         if(data.contains("[")) return data.substring(0, data.indexOf('[')); // Strip properties
@@ -54,7 +54,7 @@ public class CheckBlockFunction implements Function<String> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/EntityFunction.java

@@ -7,14 +7,14 @@
 
 package com.dfsek.terra.addons.terrascript.script.functions;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.ConstantExpression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.entity.Entity;
 import com.dfsek.terra.api.entity.EntityType;
@@ -26,12 +26,12 @@ import com.dfsek.terra.api.util.vector.Vector3;
 
 public class EntityFunction implements Function<Void> {
     private final EntityType data;
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     private final Platform platform;
     
-    public EntityFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> data, Platform platform,
-                          Position position) {
+    public EntityFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> data, Platform platform,
+                          SourcePosition position) {
         this.position = position;
         this.platform = platform;
         if(!(data instanceof ConstantExpression)) throw new ParseException("Entity data must be constant", data.getPosition());
@@ -43,12 +43,13 @@ public class EntityFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
-        Entity entity = arguments.getWorld().spawnEntity(Vector3.of(xz.getX(), y.apply(implementationArguments, scope).doubleValue(),
+        Entity entity = arguments.getWorld().spawnEntity(Vector3.of(xz.getX(), y.evaluate(implementationArguments, scope).doubleValue(),
                                                                     xz.getZ())
                                                                 .mutable()
                                                                 .add(arguments.getOrigin())
@@ -59,7 +60,7 @@ public class EntityFunction implements Function<Void> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/GetMarkFunction.java

@@ -9,22 +9,22 @@ package com.dfsek.terra.addons.terrascript.script.functions;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.util.RotationUtil;
 import com.dfsek.terra.api.util.vector.Vector2;
 import com.dfsek.terra.api.util.vector.Vector3;
 
 
 public class GetMarkFunction implements Function<String> {
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     
-    public GetMarkFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Position position) {
+    public GetMarkFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, SourcePosition position) {
         this.position = position;
         this.x = x;
         this.y = y;
@@ -32,13 +32,14 @@ public class GetMarkFunction implements Function<String> {
     }
     
     @Override
-    public String apply(ImplementationArguments implementationArguments, Scope scope) {
+    public String evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
         String mark = arguments.getMark(Vector3.of(FastMath.floorToInt(xz.getX()), FastMath.floorToInt(
-                                                           y.apply(implementationArguments, scope).doubleValue()),
+                                                           y.evaluate(implementationArguments, scope).doubleValue()),
                                                    FastMath.floorToInt(xz.getZ()))
                                                .mutable()
                                                .add(arguments.getOrigin())
@@ -47,7 +48,7 @@ public class GetMarkFunction implements Function<String> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/LootFunction.java

@@ -13,13 +13,13 @@ import org.slf4j.LoggerFactory;
 
 import java.util.Random;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.StructureScript;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.block.entity.BlockEntity;
 import com.dfsek.terra.api.block.entity.Container;
@@ -35,14 +35,14 @@ import com.dfsek.terra.api.util.vector.Vector3;
 public class LootFunction implements Function<Void> {
     private static final Logger LOGGER = LoggerFactory.getLogger(LootFunction.class);
     private final Registry<LootTable> registry;
-    private final Returnable<String> data;
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<String> data;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     private final Platform platform;
     private final StructureScript script;
     
-    public LootFunction(Registry<LootTable> registry, Returnable<Number> x, Returnable<Number> y, Returnable<Number> z,
-                        Returnable<String> data, Platform platform, Position position, StructureScript script) {
+    public LootFunction(Registry<LootTable> registry, Expression<Number> x, Expression<Number> y, Expression<Number> z,
+                        Expression<String> data, Platform platform, SourcePosition position, StructureScript script) {
         this.registry = registry;
         this.position = position;
         this.data = data;
@@ -54,23 +54,23 @@ public class LootFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()),
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
                                                arguments.getRotation());
         
         
-        String id = data.apply(implementationArguments, scope);
+        String id = data.evaluate(implementationArguments, scope);
         
         
         registry.get(RegistryKey.parse(id))
                 .ifPresentOrElse(table -> {
                                      Vector3 apply = Vector3.of(FastMath.roundToInt(xz.getX()),
-                                                                y.apply(implementationArguments, scope)
+                                                                y.evaluate(implementationArguments, scope)
                                                                  .intValue(),
                                                                 FastMath.roundToInt(xz.getZ())).mutable().add(arguments.getOrigin()).immutable();
-            
+                                     
                                      try {
                                          BlockEntity data = arguments.getWorld().getBlockEntity(apply);
                                          if(!(data instanceof Container container)) {
@@ -78,12 +78,12 @@ public class LootFunction implements Function<Void> {
                                                           apply, data);
                                              return;
                                          }
-                
+                                         
                                          LootPopulateEvent event = new LootPopulateEvent(container, table,
                                                                                          arguments.getWorld().getPack(), script);
                                          platform.getEventManager().callEvent(event);
                                          if(event.isCancelled()) return;
-                
+                                         
                                          event.getTable().fillInventory(container.getInventory(),
                                                                         new Random(apply.hashCode()));
                                          data.update(false);
@@ -97,7 +97,7 @@ public class LootFunction implements Function<Void> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/PullFunction.java

@@ -9,14 +9,14 @@ package com.dfsek.terra.addons.terrascript.script.functions;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.constants.ConstantExpression;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.block.state.BlockState;
 import com.dfsek.terra.api.util.RotationUtil;
@@ -26,11 +26,11 @@ import com.dfsek.terra.api.util.vector.Vector3;
 
 public class PullFunction implements Function<Void> {
     private final BlockState data;
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     
-    public PullFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> data, Platform platform,
-                        Position position) {
+    public PullFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> data, Platform platform,
+                        SourcePosition position) {
         this.position = position;
         if(!(data instanceof ConstantExpression)) throw new ParseException("Block data must be constant", data.getPosition());
         
@@ -41,12 +41,13 @@ public class PullFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
-        Vector3.Mutable mutable = Vector3.of(FastMath.roundToInt(xz.getX()), y.apply(implementationArguments, scope).intValue(),
+        Vector3.Mutable mutable = Vector3.of(FastMath.roundToInt(xz.getX()), y.evaluate(implementationArguments, scope).intValue(),
                                              FastMath.roundToInt(xz.getZ())).mutable().add(arguments.getOrigin());
         while(mutable.getY() > arguments.getWorld().getMinHeight()) {
             if(!arguments.getWorld().getBlockState(mutable).isAir()) {
@@ -59,7 +60,7 @@ public class PullFunction implements Function<Void> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/RandomFunction.java

@@ -7,19 +7,19 @@
 
 package com.dfsek.terra.addons.terrascript.script.functions;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class RandomFunction implements Function<Integer> {
-    private final Returnable<Number> numberReturnable;
-    private final Position position;
+    private final Expression<Number> numberReturnable;
+    private final SourcePosition position;
     
-    public RandomFunction(Returnable<Number> numberReturnable, Position position) {
+    public RandomFunction(Expression<Number> numberReturnable, SourcePosition position) {
         this.numberReturnable = numberReturnable;
         this.position = position;
     }
@@ -31,13 +31,13 @@ public class RandomFunction implements Function<Integer> {
     }
     
     @Override
-    public Integer apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Integer evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return ((TerraImplementationArguments) implementationArguments).getRandom().nextInt(
-                numberReturnable.apply(implementationArguments, scope).intValue());
+                numberReturnable.evaluate(implementationArguments, scope).intValue());
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/RecursionsFunction.java

@@ -7,17 +7,17 @@
 
 package com.dfsek.terra.addons.terrascript.script.functions;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 
 
 public class RecursionsFunction implements Function<Number> {
-    private final Position position;
+    private final SourcePosition position;
     
-    public RecursionsFunction(Position position) {
+    public RecursionsFunction(SourcePosition position) {
         this.position = position;
     }
     
@@ -27,12 +27,12 @@ public class RecursionsFunction implements Function<Number> {
     }
     
     @Override
-    public Number apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Number evaluate(ImplementationArguments implementationArguments, Scope scope) {
         return ((TerraImplementationArguments) implementationArguments).getRecursions();
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/SetMarkFunction.java

@@ -9,23 +9,24 @@ package com.dfsek.terra.addons.terrascript.script.functions;
 
 import net.jafama.FastMath;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.util.RotationUtil;
 import com.dfsek.terra.api.util.vector.Vector2;
 import com.dfsek.terra.api.util.vector.Vector3;
 
 
 public class SetMarkFunction implements Function<Void> {
-    private final Returnable<Number> x, y, z;
-    private final Position position;
-    private final Returnable<String> mark;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
+    private final Expression<String> mark;
     
-    public SetMarkFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> mark, Position position) {
+    public SetMarkFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> mark,
+                           SourcePosition position) {
         this.position = position;
         this.mark = mark;
         this.x = x;
@@ -34,22 +35,23 @@ public class SetMarkFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
         
         arguments.setMark(Vector3.of(FastMath.floorToInt(xz.getX()),
                                      FastMath.floorToInt(
-                                             y.apply(implementationArguments, scope).doubleValue()),
+                                             y.evaluate(implementationArguments, scope).doubleValue()),
                                      FastMath.floorToInt(xz.getZ())).mutable().add(arguments.getOrigin()).immutable(),
-                          mark.apply(implementationArguments, scope));
+                          mark.evaluate(implementationArguments, scope));
         return null;
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/StateFunction.java

@@ -11,12 +11,12 @@ import net.jafama.FastMath;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.block.entity.BlockEntity;
 import com.dfsek.terra.api.util.RotationUtil;
 import com.dfsek.terra.api.util.vector.Vector2;
@@ -25,12 +25,12 @@ import com.dfsek.terra.api.util.vector.Vector3;
 
 public class StateFunction implements Function<Void> {
     private static final Logger LOGGER = LoggerFactory.getLogger(StateFunction.class);
-    private final Returnable<String> data;
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<String> data;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     
-    public StateFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> data,
-                         Position position) {
+    public StateFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> data,
+                         SourcePosition position) {
         this.position = position;
         this.data = data;
         this.x = x;
@@ -39,17 +39,18 @@ public class StateFunction implements Function<Void> {
     }
     
     @Override
-    public Void apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Void evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
         
-        Vector3 origin = Vector3.of(FastMath.roundToInt(xz.getX()), y.apply(implementationArguments, scope).intValue(),
+        Vector3 origin = Vector3.of(FastMath.roundToInt(xz.getX()), y.evaluate(implementationArguments, scope).intValue(),
                                     FastMath.roundToInt(xz.getZ())).mutable().add(arguments.getOrigin()).immutable();
         try {
             BlockEntity state = arguments.getWorld().getBlockEntity(origin);
-            state.applyState(data.apply(implementationArguments, scope));
+            state.applyState(data.evaluate(implementationArguments, scope));
             state.update(false);
         } catch(Exception e) {
             LOGGER.warn("Could not apply BlockState at {}", origin, e);
@@ -59,7 +60,7 @@ public class StateFunction implements Function<Void> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
     

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/script/functions/StructureFunction.java

@@ -13,13 +13,13 @@ import org.slf4j.LoggerFactory;
 
 import java.util.List;
 
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+import com.dfsek.terra.addons.terrascript.parser.lang.Expression;
 import com.dfsek.terra.addons.terrascript.parser.lang.ImplementationArguments;
-import com.dfsek.terra.addons.terrascript.parser.lang.Returnable;
 import com.dfsek.terra.addons.terrascript.parser.lang.Scope;
 import com.dfsek.terra.addons.terrascript.parser.lang.functions.Function;
 import com.dfsek.terra.addons.terrascript.script.StructureScript;
 import com.dfsek.terra.addons.terrascript.script.TerraImplementationArguments;
-import com.dfsek.terra.addons.terrascript.tokenizer.Position;
 import com.dfsek.terra.api.Platform;
 import com.dfsek.terra.api.registry.Registry;
 import com.dfsek.terra.api.structure.Structure;
@@ -31,14 +31,14 @@ import com.dfsek.terra.api.util.vector.Vector2;
 public class StructureFunction implements Function<Boolean> {
     private static final Logger LOGGER = LoggerFactory.getLogger(StructureFunction.class);
     private final Registry<Structure> registry;
-    private final Returnable<String> id;
-    private final Returnable<Number> x, y, z;
-    private final Position position;
+    private final Expression<String> id;
+    private final Expression<Number> x, y, z;
+    private final SourcePosition position;
     private final Platform platform;
-    private final List<Returnable<String>> rotations;
+    private final List<Expression<String>> rotations;
     
-    public StructureFunction(Returnable<Number> x, Returnable<Number> y, Returnable<Number> z, Returnable<String> id,
-                             List<Returnable<String>> rotations, Registry<Structure> registry, Position position, Platform platform) {
+    public StructureFunction(Expression<Number> x, Expression<Number> y, Expression<Number> z, Expression<String> id,
+                             List<Expression<String>> rotations, Registry<Structure> registry, SourcePosition position, Platform platform) {
         this.registry = registry;
         this.id = id;
         this.position = position;
@@ -55,20 +55,21 @@ public class StructureFunction implements Function<Boolean> {
     }
     
     @Override
-    public Boolean apply(ImplementationArguments implementationArguments, Scope scope) {
+    public Boolean evaluate(ImplementationArguments implementationArguments, Scope scope) {
         TerraImplementationArguments arguments = (TerraImplementationArguments) implementationArguments;
         
         if(arguments.getRecursions() > platform.getTerraConfig().getMaxRecursion())
             throw new RuntimeException("Structure recursion too deep: " + arguments.getRecursions());
         
-        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.apply(implementationArguments, scope).doubleValue(),
-                                                          z.apply(implementationArguments, scope).doubleValue()), arguments.getRotation());
+        Vector2 xz = RotationUtil.rotateVector(Vector2.of(x.evaluate(implementationArguments, scope).doubleValue(),
+                                                          z.evaluate(implementationArguments, scope).doubleValue()),
+                                               arguments.getRotation());
         
         
-        String app = id.apply(implementationArguments, scope);
+        String app = id.evaluate(implementationArguments, scope);
         return registry.getByID(app).map(script -> {
             Rotation rotation1;
-            String rotString = rotations.get(arguments.getRandom().nextInt(rotations.size())).apply(implementationArguments, scope);
+            String rotString = rotations.get(arguments.getRandom().nextInt(rotations.size())).evaluate(implementationArguments, scope);
             try {
                 rotation1 = Rotation.valueOf(rotString);
             } catch(IllegalArgumentException e) {
@@ -80,7 +81,7 @@ public class StructureFunction implements Function<Boolean> {
                 return structureScript.generate(arguments.getOrigin(),
                                                 arguments.getWorld()
                                                          .buffer(FastMath.roundToInt(xz.getX()),
-                                                                 y.apply(implementationArguments, scope).intValue(),
+                                                                 y.evaluate(implementationArguments, scope).intValue(),
                                                                  FastMath.roundToInt(xz.getZ())),
                                                 arguments.getRandom(),
                                                 arguments.getRotation().rotate(rotation1), arguments.getRecursions() + 1);
@@ -88,7 +89,7 @@ public class StructureFunction implements Function<Boolean> {
             return script.generate(arguments.getOrigin(),
                                    arguments.getWorld()
                                             .buffer(FastMath.roundToInt(xz.getX()),
-                                                    y.apply(implementationArguments, scope).intValue(),
+                                                    y.evaluate(implementationArguments, scope).intValue(),
                                                     FastMath.roundToInt(xz.getZ())),
                                    arguments.getRandom(),
                                    arguments.getRotation().rotate(rotation1));
@@ -99,7 +100,7 @@ public class StructureFunction implements Function<Boolean> {
     }
     
     @Override
-    public Position getPosition() {
+    public SourcePosition getPosition() {
         return position;
     }
 }

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/tokenizer/Lookahead.java

@@ -1,130 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.tokenizer;
-
-
-import java.io.IOException;
-import java.io.Reader;
-import java.util.ArrayList;
-import java.util.List;
-
-
-/**
- * Stream-like data structure that allows viewing future elements without consuming current.
- */
-public class Lookahead {
-    private final List<Char> buffer = new ArrayList<>();
-    private final Reader input;
-    private int index = 0;
-    private int line = 0;
-    private boolean end = false;
-    
-    public Lookahead(Reader r) {
-        this.input = r;
-    }
-    
-    /**
-     * Get the current character without consuming it.
-     *
-     * @return current character
-     */
-    public Char current() {
-        return next(0);
-    }
-    
-    
-    /**
-     * Consume and return one character.
-     *
-     * @return Character that was consumed.
-     */
-    public Char consume() {
-        Char consumed = current();
-        consume(1);
-        return consumed;
-    }
-    
-    /**
-     * Fetch a future character without consuming it.
-     *
-     * @param ahead Distance ahead to peek
-     *
-     * @return Character
-     */
-    public Char next(int ahead) {
-        if(ahead < 0) throw new IllegalArgumentException();
-        
-        while(buffer.size() <= ahead && !end) {
-            Char item = fetch();
-            if(item != null) {
-                buffer.add(item);
-            } else end = true;
-        }
-        
-        if(ahead >= buffer.size()) {
-            return null;
-        } else return buffer.get(ahead);
-    }
-    
-    /**
-     * Consume an amount of characters
-     *
-     * @param amount Number of characters to consume
-     */
-    public void consume(int amount) {
-        if(amount < 0) throw new IllegalArgumentException();
-        while(amount-- > 0) {
-            if(!buffer.isEmpty()) buffer.remove(0); // Remove top item from buffer.
-            else {
-                if(end) return;
-                Char item = fetch();
-                if(item == null) end = true;
-            }
-        }
-    }
-    
-    public boolean matches(String check, boolean consume) {
-        if(check == null) return false;
-        
-        for(int i = 0; i < check.length(); i++) {
-            if(!next(i).is(check.charAt(i))) return false;
-        }
-        
-        if(consume) consume(check.length()); // Consume string
-        return true;
-    }
-    
-    /**
-     * Fetch the next character.
-     *
-     * @return Next character
-     */
-    private Char fetch() {
-        try {
-            int c = input.read();
-            if(c == -1) return null;
-            if(c == '\n') {
-                line++;
-                index = 0;
-            }
-            index++;
-            return new Char((char) c, line, index);
-        } catch(IOException e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-    
-    public int getLine() {
-        return line;
-    }
-    
-    public int getIndex() {
-        return index;
-    }
-}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/tokenizer/Position.java

@@ -1,23 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.tokenizer;
-
-public class Position {
-    private final int line;
-    private final int index;
-    
-    public Position(int line, int index) {
-        this.line = line;
-        this.index = index;
-    }
-    
-    @Override
-    public String toString() {
-        return (line + 1) + ":" + index;
-    }
-}

common/addons/structure-terrascript-loader/src/main/java/com/dfsek/terra/addons/terrascript/tokenizer/Tokenizer.java

@@ -1,247 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package com.dfsek.terra.addons.terrascript.tokenizer;
-
-import com.google.common.collect.Sets;
-
-import java.io.StringReader;
-import java.util.Set;
-import java.util.Stack;
-
-import com.dfsek.terra.addons.terrascript.parser.exceptions.ParseException;
-import com.dfsek.terra.addons.terrascript.tokenizer.exceptions.EOFException;
-import com.dfsek.terra.addons.terrascript.tokenizer.exceptions.FormatException;
-import com.dfsek.terra.addons.terrascript.tokenizer.exceptions.TokenizerException;
-
-
-public class Tokenizer {
-    public static final Set<Character> syntaxSignificant = Sets.newHashSet(';', '(', ')', '"', ',', '\\', '=', '{', '}', '+', '-', '*', '/',
-                                                                           '>', '<', '!'); // Reserved chars
-    private final Lookahead reader;
-    private final Stack<Token> brackets = new Stack<>();
-    private Token current;
-    private Token last;
-    
-    public Tokenizer(String data) {
-        reader = new Lookahead(new StringReader(data + '\0'));
-        current = fetchCheck();
-    }
-    
-    /**
-     * Get the first token.
-     *
-     * @return First token
-     *
-     * @throws ParseException If token does not exist
-     */
-    public Token get() {
-        if(!hasNext()) throw new ParseException("Unexpected end of input", last.getPosition());
-        return current;
-    }
-    
-    /**
-     * Consume (get and remove) the first token.
-     *
-     * @return First token
-     *
-     * @throws ParseException If token does not exist
-     */
-    public Token consume() {
-        if(!hasNext()) throw new ParseException("Unexpected end of input", last.getPosition());
-        Token temp = current;
-        current = fetchCheck();
-        return temp;
-    }
-    
-    private Token fetchCheck() {
-        Token fetch = fetch();
-        if(fetch != null) {
-            last = fetch;
-            if(fetch.getType() == Token.Type.BLOCK_BEGIN) brackets.push(fetch); // Opening bracket
-            else if(fetch.getType() == Token.Type.BLOCK_END) {
-                if(!brackets.isEmpty()) brackets.pop();
-                else throw new ParseException("Dangling opening brace", new Position(0, 0));
-            }
-        } else if(!brackets.isEmpty()) {
-            throw new ParseException("Dangling closing brace", brackets.peek().getPosition());
-        }
-        return fetch;
-    }
-    
-    private Token fetch() throws TokenizerException {
-        while(!reader.current().isEOF() && reader.current().isWhitespace()) reader.consume();
-        
-        while(reader.matches("//", true)) skipLine(); // Skip line if comment
-        
-        if(reader.matches("/*", true)) skipTo("*/"); // Skip multi line comment
-        
-        if(reader.current().isEOF()) return null; // EOF
-        
-        if(reader.matches("==", true))
-            return new Token("==", Token.Type.EQUALS_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches("!=", true))
-            return new Token("!=", Token.Type.NOT_EQUALS_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches(">=", true))
-            return new Token(">=", Token.Type.GREATER_THAN_OR_EQUALS_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches("<=", true))
-            return new Token("<=", Token.Type.LESS_THAN_OR_EQUALS_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches(">", true))
-            return new Token(">", Token.Type.GREATER_THAN_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches("<", true))
-            return new Token("<", Token.Type.LESS_THAN_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        
-        
-        if(reader.matches("||", true))
-            return new Token("||", Token.Type.BOOLEAN_OR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.matches("&&", true))
-            return new Token("&&", Token.Type.BOOLEAN_AND, new Position(reader.getLine(), reader.getIndex()));
-        
-        
-        if(isNumberStart()) {
-            StringBuilder num = new StringBuilder();
-            while(!reader.current().isEOF() && isNumberLike()) {
-                num.append(reader.consume());
-            }
-            return new Token(num.toString(), Token.Type.NUMBER, new Position(reader.getLine(), reader.getIndex()));
-        }
-        
-        if(reader.current().is('"')) {
-            reader.consume(); // Consume first quote
-            StringBuilder string = new StringBuilder();
-            boolean ignoreNext = false;
-            while((!reader.current().is('"')) || ignoreNext) {
-                if(reader.current().is('\\') && !ignoreNext) {
-                    ignoreNext = true;
-                    reader.consume();
-                    continue;
-                } else ignoreNext = false;
-                if(reader.current().isEOF())
-                    throw new FormatException("No end of string literal found. ", new Position(reader.getLine(), reader.getIndex()));
-                string.append(reader.consume());
-            }
-            reader.consume(); // Consume last quote
-            
-            return new Token(string.toString(), Token.Type.STRING, new Position(reader.getLine(), reader.getIndex()));
-        }
-        
-        if(reader.current().is('('))
-            return new Token(reader.consume().toString(), Token.Type.GROUP_BEGIN, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is(')'))
-            return new Token(reader.consume().toString(), Token.Type.GROUP_END, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is(';'))
-            return new Token(reader.consume().toString(), Token.Type.STATEMENT_END, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is(','))
-            return new Token(reader.consume().toString(), Token.Type.SEPARATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('{'))
-            return new Token(reader.consume().toString(), Token.Type.BLOCK_BEGIN, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('}'))
-            return new Token(reader.consume().toString(), Token.Type.BLOCK_END, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('='))
-            return new Token(reader.consume().toString(), Token.Type.ASSIGNMENT, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('+'))
-            return new Token(reader.consume().toString(), Token.Type.ADDITION_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('-'))
-            return new Token(reader.consume().toString(), Token.Type.SUBTRACTION_OPERATOR,
-                             new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('*'))
-            return new Token(reader.consume().toString(), Token.Type.MULTIPLICATION_OPERATOR,
-                             new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('/'))
-            return new Token(reader.consume().toString(), Token.Type.DIVISION_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('%'))
-            return new Token(reader.consume().toString(), Token.Type.MODULO_OPERATOR, new Position(reader.getLine(), reader.getIndex()));
-        if(reader.current().is('!'))
-            return new Token(reader.consume().toString(), Token.Type.BOOLEAN_NOT, new Position(reader.getLine(), reader.getIndex()));
-        
-        StringBuilder token = new StringBuilder();
-        while(!reader.current().isEOF() && !isSyntaxSignificant(reader.current().getCharacter())) {
-            Char c = reader.consume();
-            if(c.isWhitespace()) break;
-            token.append(c);
-        }
-        
-        String tokenString = token.toString();
-        
-        if(tokenString.equals("true"))
-            return new Token(tokenString, Token.Type.BOOLEAN, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("false"))
-            return new Token(tokenString, Token.Type.BOOLEAN, new Position(reader.getLine(), reader.getIndex()));
-        
-        if(tokenString.equals("num"))
-            return new Token(tokenString, Token.Type.NUMBER_VARIABLE, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("str"))
-            return new Token(tokenString, Token.Type.STRING_VARIABLE, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("bool"))
-            return new Token(tokenString, Token.Type.BOOLEAN_VARIABLE, new Position(reader.getLine(), reader.getIndex()));
-        
-        if(tokenString.equals("if"))
-            return new Token(tokenString, Token.Type.IF_STATEMENT, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("else"))
-            return new Token(tokenString, Token.Type.ELSE, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("while"))
-            return new Token(tokenString, Token.Type.WHILE_LOOP, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("for"))
-            return new Token(tokenString, Token.Type.FOR_LOOP, new Position(reader.getLine(), reader.getIndex()));
-        
-        if(tokenString.equals("return"))
-            return new Token(tokenString, Token.Type.RETURN, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("continue"))
-            return new Token(tokenString, Token.Type.CONTINUE, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("break"))
-            return new Token(tokenString, Token.Type.BREAK, new Position(reader.getLine(), reader.getIndex()));
-        if(tokenString.equals("fail"))
-            return new Token(tokenString, Token.Type.FAIL, new Position(reader.getLine(), reader.getIndex()));
-        
-        return new Token(tokenString, Token.Type.IDENTIFIER, new Position(reader.getLine(), reader.getIndex()));
-    }
-    
-    private void skipLine() {
-        while(!reader.current().isEOF() && !reader.current().isNewLine()) reader.consume();
-        consumeWhitespace();
-    }
-    
-    private void consumeWhitespace() {
-        while(!reader.current().isEOF() && reader.current().isWhitespace()) reader.consume(); // Consume whitespace.
-    }
-    
-    private void skipTo(String s) throws EOFException {
-        Position begin = new Position(reader.getLine(), reader.getIndex());
-        while(!reader.current().isEOF()) {
-            if(reader.matches(s, true)) {
-                consumeWhitespace();
-                return;
-            }
-            reader.consume();
-        }
-        throw new EOFException("No end of expression found.", begin);
-    }
-    
-    /**
-     * Whether this {@code Tokenizer} contains additional tokens.
-     *
-     * @return {@code true} if more tokens are present, otherwise {@code false}
-     */
-    public boolean hasNext() {
-        return !(current == null);
-    }
-    
-    private boolean isNumberLike() {
-        return reader.current().isDigit()
-               || reader.current().is('_', '.', 'E');
-    }
-    
-    private boolean isNumberStart() {
-        return reader.current().isDigit()
-               || reader.current().is('.') && reader.next(1).isDigit();
-    }
-    
-    public boolean isSyntaxSignificant(char c) {
-        return syntaxSignificant.contains(c);
-    }
-    
-}

common/addons/structure-terrascript-loader/src/test/java/structure/LookaheadStreamTest.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2020-2021 Polyhedral Development
+ *
+ * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in this module's root directory.
+ */
+
+package structure;
+
+import com.dfsek.terra.addons.terrascript.lexer.LookaheadStream;
+import com.dfsek.terra.addons.terrascript.lexer.Char;
+
+import com.dfsek.terra.addons.terrascript.lexer.SourcePosition;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+
+public class LookaheadStreamTest {
+    @Test
+    public void lookahead() {
+        String testString = "Test string...\nNew line";
+        
+        LookaheadStream lookahead = new LookaheadStream(testString);
+        
+        Char first = new Char('T', new SourcePosition(1, 1));
+        Char second = new Char('e', new SourcePosition(1, 2));
+        Char third = new Char('s', new SourcePosition(1, 3));
+        Char space = new Char(' ', new SourcePosition(1, 5));
+        Char newline = new Char('\n', new SourcePosition(1, 15));
+        Char lineTwoColOne = new Char('N', new SourcePosition(2, 1));
+        String lineTwo = "New line";
+        
+        assertTrue(lookahead.matchesString("Test", false));
+        assertTrue(lookahead.matchesString(testString, false));
+        assertFalse(lookahead.matchesString(testString + "asdf", false));
+        assertFalse(lookahead.matchesString("Foo", false));
+        
+        assertEquals(first, lookahead.current());
+        assertEquals(first, lookahead.current());
+
+        assertEquals(new SourcePosition(1, 1), lookahead.getPosition());
+        assertEquals(new SourcePosition(1, 1), lookahead.getPosition());
+        
+        assertEquals(second, lookahead.peek());
+        assertEquals(second, lookahead.peek());
+        
+        assertEquals(first, lookahead.consume());
+        
+        assertFalse(lookahead.matchesString(testString, false));
+        
+        assertEquals(second, lookahead.current());
+        
+        assertEquals(second, lookahead.consume());
+
+        assertEquals(third, lookahead.current());
+        
+        assertTrue(lookahead.matchesString("st", true));
+        
+        assertEquals(space, lookahead.current());
+        
+        assertEquals(space, lookahead.consume());
+        
+        assertTrue(lookahead.matchesString("string...", false));
+        assertTrue(lookahead.matchesString("string...", true));
+        assertFalse(lookahead.matchesString("string...", false));
+        
+        assertEquals(newline, lookahead.current());
+        assertEquals(newline, lookahead.consume());
+        
+        assertEquals(lineTwoColOne, lookahead.current());
+        
+        assertTrue(lookahead.matchesString(lineTwo, false));
+        assertFalse(lookahead.matchesString(lineTwo + "asdf", false));
+        assertTrue(lookahead.matchesString(lineTwo, true));
+        
+        assertEquals(new SourcePosition(2, 8), lookahead.getPosition());
+        
+        assertDoesNotThrow(lookahead::consume);
+        assertEquals(new SourcePosition(2, 8), lookahead.getPosition());
+        
+        assertDoesNotThrow(lookahead::consume);
+        assertEquals(new SourcePosition(2, 8), lookahead.getPosition());
+    }
+}

common/addons/structure-terrascript-loader/src/test/java/structure/LookaheadTest.java

@@ -1,29 +0,0 @@
-/*
- * Copyright (c) 2020-2021 Polyhedral Development
- *
- * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in this module's root directory.
- */
-
-package structure;
-
-import org.junit.jupiter.api.Test;
-
-import java.io.StringReader;
-
-import com.dfsek.terra.addons.terrascript.tokenizer.Lookahead;
-
-
-public class LookaheadTest {
-    @Test
-    public void lookahead() {
-        Lookahead lookahead = new Lookahead(new StringReader("Test string..."));
-        
-        for(int i = 0; lookahead.next(i) != null; i++) {
-            System.out.print(lookahead.next(i).getCharacter());
-        }
-        while(lookahead.next(0) != null) {
-            System.out.print(lookahead.consume().getCharacter());
-        }
-    }
-}