From ad5823055de2c297c570bd491021efe80264a4ca Mon Sep 17 00:00:00 2001
From: dfsek <dfsek@protonmail.com>
Date: Thu, 31 Dec 2020 02:03:47 -0700
Subject: [PATCH] do precedence better

---
 .../terra/api/structures/parser/Parser.java   |  2 +-
 .../api/structures/parser/ParserUtil.java     | 23 +++++++++++++++++++
 common/src/test/resources/test.tesf           |  9 +++++++-
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/common/src/main/java/com/dfsek/terra/api/structures/parser/Parser.java b/common/src/main/java/com/dfsek/terra/api/structures/parser/Parser.java
index 0443827f9..78f9cbfea 100644
--- a/common/src/main/java/com/dfsek/terra/api/structures/parser/Parser.java
+++ b/common/src/main/java/com/dfsek/terra/api/structures/parser/Parser.java
@@ -286,7 +286,7 @@ public class Parser {
         Returnable<?> right = parseExpression(tokens, false, variableMap);
 
         Token other = tokens.get();
-        if(other.isBinaryOperator() && (other.getType().equals(Token.Type.MULTIPLICATION_OPERATOR) || other.getType().equals(Token.Type.DIVISION_OPERATOR))) {
+        if(ParserUtil.hasPrecedence(binaryOperator.getType(), other.getType())) {
             return assemble(left, parseBinaryOperation(right, tokens, variableMap), binaryOperator);
         } else if(other.isBinaryOperator()) {
             return parseBinaryOperation(assemble(left, right, binaryOperator), tokens, variableMap);
diff --git a/common/src/main/java/com/dfsek/terra/api/structures/parser/ParserUtil.java b/common/src/main/java/com/dfsek/terra/api/structures/parser/ParserUtil.java
index c54169044..e42349ac1 100644
--- a/common/src/main/java/com/dfsek/terra/api/structures/parser/ParserUtil.java
+++ b/common/src/main/java/com/dfsek/terra/api/structures/parser/ParserUtil.java
@@ -5,8 +5,26 @@ import com.dfsek.terra.api.structures.parser.lang.Returnable;
 import com.dfsek.terra.api.structures.tokenizer.Token;
 
 import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 public class ParserUtil {
+
+    private static final Map<Token.Type, List<Token.Type>> PRECEDENCE = new HashMap<>();
+    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);
+
+    static { // Setup precedence
+        PRECEDENCE.put(Token.Type.ADDITION_OPERATOR, Arrays.asList(Token.Type.MULTIPLICATION_OPERATOR, Token.Type.DIVISION_OPERATOR));
+        PRECEDENCE.put(Token.Type.SUBTRACTION_OPERATOR, Arrays.asList(Token.Type.MULTIPLICATION_OPERATOR, Token.Type.DIVISION_OPERATOR));
+        PRECEDENCE.put(Token.Type.EQUALS_OPERATOR, ARITHMETIC);
+        PRECEDENCE.put(Token.Type.NOT_EQUALS_OPERATOR, ARITHMETIC);
+        PRECEDENCE.put(Token.Type.GREATER_THAN_OPERATOR, ARITHMETIC);
+        PRECEDENCE.put(Token.Type.GREATER_THAN_OR_EQUALS_OPERATOR, ARITHMETIC);
+        PRECEDENCE.put(Token.Type.LESS_THAN_OPERATOR, ARITHMETIC);
+        PRECEDENCE.put(Token.Type.LESS_THAN_OR_EQUALS_OPERATOR, ARITHMETIC);
+    }
+
     public static void checkType(Token token, Token.Type... expected) throws ParseException {
         for(Token.Type type : expected) if(token.getType().equals(type)) return;
         throw new ParseException("Expected " + Arrays.toString(expected) + " but found " + token.getType(), token.getPosition());
@@ -59,4 +77,9 @@ public class ParserUtil {
                 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;
+        return PRECEDENCE.get(first).contains(second);
+    }
 }
diff --git a/common/src/test/resources/test.tesf b/common/src/test/resources/test.tesf
index 8743834b1..f1108abda 100644
--- a/common/src/test/resources/test.tesf
+++ b/common/src/test/resources/test.tesf
@@ -7,6 +7,11 @@ num testVar = 3.4;
 bool boolean = true;
 str stringVar = "hello!";
 
+num precedence = 2 + 2 * 2;
+test("precedence: " + precedence, 2);
+num precedence2 = 2 * 2 + 2;
+test("precedence 2: " + precedence2, 2);
+
 bool iftest = false;
 
 bool truetest = false;
@@ -19,7 +24,9 @@ for(num i = 0; i < 5; i = i + 1) {
 
 for(num j = 0; j < 5; j = j + 1) test("single statement j = " + j, iterator);
 
-
+if(4 + 2 == 2 + 4) {
+    test("new thing " + 2, iterator);
+}
 
 while(iterator < 5) {
     test("always, even after " + 2, iterator);