From 69ab5f074540a550393806de1a32d70d1c895121 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 31 Jul 2026 11:14:00 +0100
Subject: Use class for singleton structs

---
 .../generators/javatypes/JavaTypesGenerator.java   | 38 ++++++++++++++++------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatypes/JavaTypesGenerator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatypes/JavaTypesGenerator.java
index e8ecaa7..e1aca6d 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatypes/JavaTypesGenerator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatypes/JavaTypesGenerator.java
@@ -118,10 +118,12 @@ public class JavaTypesGenerator implements Generator {
         );
     }
 
-    private JavaRecordDeclaration generateStructDefinition(
+    private JavaTypeDeclaration generateStructDefinition(
         TypedStructDefinitionNode structDefinition,
         Context context
     ) {
+        var javaTypeRef = generateTypeRef(structDefinition.type(), context);
+
         var components = structDefinition.fields().orElse(List.of()).stream()
             .map(field -> new JavaRecordComponent(
                 generateTypeRef(field.type(), context),
@@ -148,13 +150,20 @@ public class JavaTypesGenerator implements Generator {
             body.add(new JavaFieldDeclaration(
                 JavaVisibility.PUBLIC,
                 JavaMemberKind.STATIC,
-                this.generateTypeRef(structDefinition.type(), context),
+                javaTypeRef,
                 JavaGenerator.INSTANCE_FIELD_NAME,
                 Optional.of(new JavaNewExpression(
-                    generateTypeRef(structDefinition.type(), context),
+                    javaTypeRef,
                     List.of()
                 ))
             ));
+
+            body.add(new JavaConstructorDeclaration(
+                javaTypeRef.typeNames().getLast(),
+                JavaVisibility.PRIVATE,
+                List.of(),
+                new JavaBlock(List.of())
+            ));
         }
 
         body.add(new JavaMethodDeclaration(
@@ -175,13 +184,22 @@ public class JavaTypesGenerator implements Generator {
             context
         ));
 
-        return new JavaRecordDeclaration(
-            generateTypeRef(structDefinition.type(), context),
-            components,
-            implementsTypes,
-            body,
-            structDefinition.docComment()
-        );
+        if (structDefinition.fields().isPresent()) {
+            return new JavaRecordDeclaration(
+                javaTypeRef,
+                components,
+                implementsTypes,
+                body,
+                structDefinition.docComment()
+            );
+        } else {
+            return new JavaClassDeclaration(
+                javaTypeRef,
+                implementsTypes,
+                body,
+                structDefinition.docComment()
+            );
+        }
     }
 
     private JavaRecordDeclaration generateStructDefinitionBuilder(
-- 
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