Support options in Java transient-0

2 files changed, 94 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
index 5feba05..59dcefe 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
@@ -433,6 +433,8 @@ public class JavaTransient0Generator implements Generator {
             case ConstructedNativeType constructedNativeType -> {
                 if (constructedNativeType.constructor().equals(NativeTypes.LIST)) {
                     yield generateEncodeList(value, constructedNativeType.args().getFirst());
+                } else if (constructedNativeType.constructor().equals(NativeTypes.OPTION)) {
+                    yield generateEncodeOption(value, constructedNativeType.args().getFirst());
                 } else {
                     throw new UnsupportedOperationException("TODO");
                 }
@@ -491,6 +493,8 @@ public class JavaTransient0Generator implements Generator {
             case ConstructedNativeType constructedNativeType -> {
                 if (constructedNativeType.constructor().equals(NativeTypes.LIST)) {
                     yield generateDecodeList(target, constructedNativeType.args().getFirst());
+                } else if (constructedNativeType.constructor().equals(NativeTypes.OPTION)) {
+                    yield generateDecodeOption(target, constructedNativeType.args().getFirst());
                 } else {
                     throw new UnsupportedOperationException("TODO");
                 }
@@ -633,6 +637,88 @@ public class JavaTransient0Generator implements Generator {
         return statements;
     }
 
+    private List<JavaBlockStatement> generateEncodeOption(
+        JavaExpression value,
+        Type elementType
+    ) {
+        var statements = new ArrayList<JavaBlockStatement>();
+        var isPresent = new JavaMethodCall(
+            value,
+            JavaIdentifier.of("isPresent"),
+            List.of()
+        );
+
+        statements.addAll(generateEncode(
+            isPresent,
+            NativeTypes.BOOL
+        ));
+
+        statements.add(new JavaIfStatement(
+            isPresent,
+            new JavaBlock(generateEncode(
+                new JavaMethodCall(
+                    value,
+                    JavaIdentifier.of("get"),
+                    List.of()
+                ),
+                elementType
+            )),
+            new JavaBlock(List.of())
+        ));
+
+        return statements;
+    }
+
+    private List<JavaBlockStatement> generateDecodeOption(
+        JavaIdentifier target,
+        Type elementType
+    ) {
+        var isPresent = JavaIdentifier.of(target.value() + "$isPresent");
+        var element = JavaIdentifier.of(target.value() + "$element");
+
+        var statements = new ArrayList<JavaBlockStatement>();
+
+        statements.addAll(generateDecode(isPresent, NativeTypes.BOOL));
+
+        statements.add(new JavaLocalVariableDeclaration(
+            Optional.of(JavaTypeRef.optional(this.javaGenerator.generateReferenceTypeRef(elementType))),
+            target,
+            Optional.empty()
+        ));
+
+        var ifTrue = new ArrayList<JavaBlockStatement>();
+
+        ifTrue.addAll(generateDecode(element, elementType));
+
+        ifTrue.add(new JavaExpressionStatement(new JavaBinaryOperation(
+            JavaBinaryOperator.ASSIGN,
+            new JavaRef(target),
+            new JavaStaticMethodCall(
+                JavaTypeRef.OPTIONAL,
+                JavaIdentifier.of("of"),
+                List.of(new JavaRef(element))
+            )
+        )));
+
+        statements.add(new JavaIfStatement(
+            new JavaRef(isPresent),
+            new JavaBlock(ifTrue),
+            new JavaBlock(List.of(
+                new JavaExpressionStatement(new JavaBinaryOperation(
+                    JavaBinaryOperator.ASSIGN,
+                    new JavaRef(target),
+                    new JavaStaticMethodCall(
+                        JavaTypeRef.OPTIONAL,
+                        JavaIdentifier.of("empty"),
+                        List.of()
+                    )
+                ))
+            ))
+        ));
+
+        return statements;
+    }
+
     private static JavaMethodCall generateOutputStreamWrite(JavaExpression byteToWrite) {
         return new JavaMethodCall(
             new JavaRef(OUTPUT_STREAM_NAME),
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaTypeRef.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaTypeRef.java
index 0975e4e..8dbca61 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaTypeRef.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaTypeRef.java
@@ -75,6 +75,14 @@ public record JavaTypeRef(JavaPackageName packageName, List<JavaIdentifier> type
 
     public static final JavaTypeRef OPTIONAL = topLevel(JavaPackages.JAVA_UTIL, JavaIdentifier.of("Optional"));
 
+    public static JavaTypeRef optional(JavaTypeRef elementType) {
+        return new JavaTypeRef(
+            OPTIONAL.packageName,
+            OPTIONAL.typeNames,
+            List.of(JavaTypeArg.invariant(elementType))
+        );
+    }
+
     public static final JavaTypeRef OUTPUT_STREAM = topLevel(JavaPackages.JAVA_IO, JavaIdentifier.of("OutputStream"));
 
     public static final JavaTypeRef STANDARD_CHARSETS = topLevel(JavaPackages.JAVA_NIO_CHARSET, JavaIdentifier.of("StandardCharsets"));