From de8478112ac78e9d67b3f6ca258786de559247eb Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 5 Jul 2026 12:50:02 +0100
Subject: Add equality operators to Java AST

---
 hobgoblin/src/output/lang/java/ast.hob             |  2 ++
 .../compiler/output/lang/java/JavaWriter.java      |  6 +++++
 .../output/lang/java/ast/JavaBinaryOperator.java   |  2 ++
 .../compiler/output/lang/java/JavaWriterTests.java | 26 ++++++++++++++++++++++
 4 files changed, 36 insertions(+)

diff --git a/hobgoblin/src/output/lang/java/ast.hob b/hobgoblin/src/output/lang/java/ast.hob
index 7910f79..18c86f0 100644
--- a/hobgoblin/src/output/lang/java/ast.hob
+++ b/hobgoblin/src/output/lang/java/ast.hob
@@ -180,7 +180,9 @@ enum JavaBinaryOperator {
     variant assign;
     variant bitwiseAnd;
     variant bitwiseOr;
+    variant equalTo;
     variant leftShift;
+    variant notEqualTo;
     variant unsignedRightShift;
 }
 
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
index 04f7736..1e13863 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
@@ -53,7 +53,9 @@ public class JavaWriter implements AutoCloseable {
             case ASSIGN -> "=";
             case BITWISE_AND -> "&";
             case BITWISE_OR -> "|";
+            case EQUAL_TO -> "==";
             case LEFT_SHIFT -> "<<";
+            case NOT_EQUAL_TO -> "!=";
             case UNSIGNED_RIGHT_SHIFT -> ">>>";
         });
         this.writer.write(" ");
@@ -69,7 +71,9 @@ public class JavaWriter implements AutoCloseable {
             case ASSIGN -> false;
             case BITWISE_AND -> true;
             case BITWISE_OR -> true;
+            case EQUAL_TO -> true;
             case LEFT_SHIFT -> true;
+            case NOT_EQUAL_TO -> true;
             case UNSIGNED_RIGHT_SHIFT -> true;
         };
     }
@@ -362,7 +366,9 @@ public class JavaWriter implements AutoCloseable {
             case ASSIGN -> JavaPrecedence.ASSIGNMENT;
             case BITWISE_AND -> JavaPrecedence.BITWISE_AND;
             case BITWISE_OR -> JavaPrecedence.BITWISE_INCLUSIVE_OR;
+            case EQUAL_TO -> JavaPrecedence.EQUALITY;
             case LEFT_SHIFT -> JavaPrecedence.SHIFT;
+            case NOT_EQUAL_TO -> JavaPrecedence.EQUALITY;
             case UNSIGNED_RIGHT_SHIFT -> JavaPrecedence.SHIFT;
         };
     }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBinaryOperator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBinaryOperator.java
index 162fefd..a3284e6 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBinaryOperator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBinaryOperator.java
@@ -9,7 +9,9 @@ public enum JavaBinaryOperator {
     ASSIGN,
     BITWISE_AND,
     BITWISE_OR,
+    EQUAL_TO,
     LEFT_SHIFT,
+    NOT_EQUAL_TO,
     UNSIGNED_RIGHT_SHIFT
 
     // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.java.ast.JavaBinaryOperator body
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
index b888375..1ce78ea 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
@@ -880,6 +880,32 @@ public class JavaWriterTests {
         assertThat(string, equalTo("x = 42"));
     }
 
+    @Test
+    public void binaryOperationEqualTo() throws IOException {
+        var java = new JavaBinaryOperation(
+            JavaBinaryOperator.EQUAL_TO,
+            new JavaRef(JavaIdentifier.of("x")),
+            new JavaRef(JavaIdentifier.of("y"))
+        );
+
+        var string = write(writer -> writer.writeTopLevelExpression(java));
+
+        assertThat(string, equalTo("x == y"));
+    }
+
+    @Test
+    public void binaryOperationNotEqualTo() throws IOException {
+        var java = new JavaBinaryOperation(
+            JavaBinaryOperator.NOT_EQUAL_TO,
+            new JavaRef(JavaIdentifier.of("x")),
+            new JavaRef(JavaIdentifier.of("y"))
+        );
+
+        var string = write(writer -> writer.writeTopLevelExpression(java));
+
+        assertThat(string, equalTo("x != y"));
+    }
+
     @Test
     public void binaryOperationUnsignedLeftShift() throws IOException {
         var java = JavaBinaryOperation.arbitrary()
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