Begin work on tokenizer

src/main/java/com/dfsek/terra/structure/v2/Function.java

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+package com.dfsek.terra.structure.v2;
+
+public interface Function {
+    void apply();
+}

src/main/java/com/dfsek/terra/structure/v2/Parser.java

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+package com.dfsek.terra.structure.v2;
+
+public class Parser {
+}

src/main/java/com/dfsek/terra/structure/v2/tokenizer/Char.java

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+package com.dfsek.terra.structure.v2.tokenizer;
+
+public class Char {
+    private final char character;
+    private final int index;
+    private final int line;
+
+
+    public Char(char character, int index, int line) {
+        this.character = character;
+        this.index = index;
+        this.line = line;
+    }
+
+    public char getCharacter() {
+        return character;
+    }
+
+    public int getIndex() {
+        return index;
+    }
+
+    public int getLine() {
+        return line;
+    }
+
+    public boolean is(char... tests) {
+        for(char test : tests) {
+            if(test == character && test != '\0') {
+                return true;
+            }
+        }
+        return false;
+    }
+}

src/main/java/com/dfsek/terra/structure/v2/tokenizer/Lookahead.java

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+package com.dfsek.terra.structure.v2.tokenizer;
+
+import org.polydev.gaea.util.GlueList;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.List;
+
+public class Lookahead {
+    private final List<Char> buffer = new GlueList<>();
+    private final Reader input;
+    private int index = 0;
+    private int line = 0;
+    private boolean end = false;
+
+    public Lookahead(Reader r) {
+        this.input = r;
+    }
+
+    public Char current() {
+        return next(0);
+    }
+
+    public Char consume() {
+        Char consumed = current();
+        consume(1);
+        return consumed;
+    }
+
+    /**
+     * Fetch and consume 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;
+        }
+    }
+
+    /**
+     * 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);
+    }
+
+    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;
+            }
+        }
+    }
+}

src/main/java/com/dfsek/terra/structure/v2/tokenizer/Tokenizer.java

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+package com.dfsek.terra.structure.v2.tokenizer;
+
+import java.io.StringReader;
+
+public class Tokenizer {
+    private final Lookahead reader;
+
+    public Tokenizer(String data) {
+        reader = new Lookahead(new StringReader(data));
+    }
+}

src/main/java/com/dfsek/terra/structure/v2/tokenizer/Tokens.java

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+package com.dfsek.terra.structure.v2.tokenizer;
+
+public enum Tokens {
+    FUNCTION, SEPARATOR, ARGUMENT
+}

src/test/java/structure/LookaheadTest.java

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+package structure;
+
+import com.dfsek.terra.structure.v2.tokenizer.Lookahead;
+import org.junit.jupiter.api.Test;
+
+import java.io.StringReader;
+
+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());
+        }
+    }
+}