Add return type to functions

4 files changed, 42 insertions, 10 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
index 432a4ba..1e93d1d 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriter.java
@@ -128,7 +128,15 @@ public class RustWriter implements AutoCloseable {
             }
         );
 
-        this.writer.write(") {");
+        this.writer.write(") ");
+
+        if (function.returnType().isPresent()) {
+            this.writer.write("-> ");
+            this.writeType(function.returnType().get());
+            this.writer.write(" ");
+        }
+
+        this.writer.write("{");
         this.writer.newLine();
         this.writer.write("}");
     }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunction.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunction.java
index 984aae4..b0dda9d 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunction.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunction.java
@@ -5,38 +5,42 @@ package org.zwobble.hobgoblin.compiler.output.lang.rust.ast;
 // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction imports
 // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction imports
 
-public record RustFunction(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name, java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam> params) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustAssociatedItem {
+public record RustFunction(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name, java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam> params, java.util.Optional<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustType> returnType) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustAssociatedItem {
     public static org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder arbitrary() {
-        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.arbitrary().build(), java.util.List.of());
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.arbitrary().build(), java.util.List.of(), java.util.Optional.empty());
     }
 
-    public record Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name, java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam> params) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustAssociatedItem.Builder {
+    public record Builder(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name, java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam> params, java.util.Optional<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustType> returnType) implements org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustAssociatedItem.Builder {
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction build() {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction(name, params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction(name, params, returnType);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder withName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier name) {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params, returnType);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder withName(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustIdentifier.Builder name) {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name.build(), params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name.build(), params, returnType);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder withParams(java.util.List<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam> params) {
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params, returnType);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder addParam(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam param) {
             var params = new java.util.ArrayList<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam>(this.params);
             params.add(param);
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params, returnType);
         }
 
         public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder addParam(org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam.Builder param) {
             var params = new java.util.ArrayList<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionParam>(this.params);
             params.add(param.build());
-            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params);
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params, returnType);
+        }
+
+        public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder withReturnType(java.util.Optional<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustType> returnType) {
+            return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder(name, params, returnType);
         }
 
         // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction.Builder body
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
index dd1729b..b7e3047 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/RustWriterTests.java
@@ -156,6 +156,20 @@ public class RustWriterTests {
     }
 
     @Test
+    public void functionWithReturnType() throws IOException {
+        var rust = RustFunction.arbitrary()
+            .withName(new RustIdentifier("area"))
+            .withReturnType(Optional.of(RustTypePath.of("i32")))
+            .build();
+
+        var string = write(writer -> writer.writeAssociatedItem(rust));
+
+        assertThat(string, equalTo("""
+            fn area() -> i32 {
+            }"""));
+    }
+
+    @Test
     public void emptyInherentImpl() throws IOException {
         var rust = RustInherentImpl.arbitrary().withType(RustTypePath.of("Square")).build();
 
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunctionMatcher.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunctionMatcher.java
index ac6d126..1526d18 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunctionMatcher.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/rust/ast/RustFunctionMatcher.java
@@ -40,6 +40,12 @@ public class RustFunctionMatcher implements org.zwobble.precisely.Matcher<java.l
         return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionMatcher(submatchers);
     }
 
+    public org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionMatcher withReturnType(org.zwobble.precisely.Matcher<? super java.util.Optional<org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustType>> returnType) {
+        var submatchers = new java.util.ArrayList<org.zwobble.precisely.Matcher<? super org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction>>(this.submatchers);
+        submatchers.add(org.zwobble.precisely.Matchers.has("returnType", org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunction::returnType, returnType));
+        return new org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionMatcher(submatchers);
+    }
+
     // Custom area start: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionMatcher body
     // Custom area end: org.zwobble.hobgoblin.compiler.output.lang.rust.ast.RustFunctionMatcher body
 }