Read lambdas with arguments

4 files changed, 61 insertions, 16 deletions

diff --git a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
index ba80bf4..cca29dc 100644
--- a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
+++ b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
@@ -2,14 +2,11 @@ package org.zwobble.couscous.frontends.java;
 
 import com.google.common.collect.ImmutableList;
 import org.eclipse.jdt.core.dom.*;
-import org.zwobble.couscous.ast.ClassNode;
-import org.zwobble.couscous.ast.ClassNodeBuilder;
-import org.zwobble.couscous.ast.StatementNode;
-import org.zwobble.couscous.ast.TypeName;
+import org.zwobble.couscous.ast.*;
+import org.zwobble.couscous.ast.VariableDeclaration;
 
 import java.io.IOException;
 import java.nio.file.Path;
-import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 import java.util.stream.Stream;
@@ -114,7 +111,7 @@ public class JavaReader {
 
     private interface FunctionDeclaration {
         List<IAnnotationBinding> getAnnotations();
-        List<SingleVariableDeclaration> parameters();
+        Stream<FormalArgumentNode> getFormalArguments();
         // TODO: add tests around void methods
         Stream<StatementNode> getBody();
     }
@@ -131,10 +128,11 @@ public class JavaReader {
             return asList(method.resolveBinding().getAnnotations());
         }
 
-        @SuppressWarnings("unchecked")
         @Override
-        public List<SingleVariableDeclaration> parameters() {
-            return method.parameters();
+        public Stream<FormalArgumentNode> getFormalArguments() {
+            @SuppressWarnings("unchecked")
+            List<SingleVariableDeclaration> parameters = method.parameters();
+            return parameters.stream().map(parameter -> readSingleVariableDeclaration(parameter));
         }
 
         @Override
@@ -164,8 +162,21 @@ public class JavaReader {
         }
 
         @Override
-        public List<SingleVariableDeclaration> parameters() {
-            return Collections.emptyList();
+        public Stream<FormalArgumentNode> getFormalArguments() {
+            return ((List<?>)expression.parameters()).stream()
+                .map(this::readParameter);
+        }
+
+        private FormalArgumentNode readParameter(Object parameter) {
+            if (parameter instanceof SingleVariableDeclaration) {
+                return readSingleVariableDeclaration((SingleVariableDeclaration) parameter);
+            } else {
+                VariableDeclarationFragment fragment = (VariableDeclarationFragment)parameter;
+                return FormalArgumentNode.formalArg(VariableDeclaration.var(
+                    fragment.resolveBinding().getKey(),
+                    fragment.getName().getIdentifier(),
+                    typeOf(fragment.resolveBinding().getType())));
+            }
         }
 
         @SuppressWarnings("unchecked")
@@ -191,10 +202,7 @@ public class JavaReader {
         for (IAnnotationBinding annotation : method.getAnnotations()) {
             builder.annotation(typeOf(annotation.getAnnotationType()));
         }
-        for (Object parameterObject : method.parameters()) {
-            SingleVariableDeclaration parameter = (SingleVariableDeclaration)parameterObject;
-            builder.argument(parameter.resolveBinding().getKey(), parameter.getName().getIdentifier(), typeOf(parameter.resolveBinding()));
-        }
+        method.getFormalArguments().forEach(builder::argument);
         method.getBody().forEach(builder::statement);
         return builder;
     }
@@ -210,6 +218,13 @@ public class JavaReader {
         return ast.getPackage().getName().getFullyQualifiedName() + "." + type.getName().getFullyQualifiedName();
     }
 
+    private FormalArgumentNode readSingleVariableDeclaration(SingleVariableDeclaration parameter) {
+        return FormalArgumentNode.formalArg(VariableDeclaration.var(
+            parameter.resolveBinding().getKey(),
+            parameter.getName().getIdentifier(),
+            typeOf(parameter.resolveBinding())));
+    }
+
     private JavaExpressionReader expressionReader() {
         return new JavaExpressionReader(this);
     }
diff --git a/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java b/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
index 6b7b5d3..cc0e5af 100644
--- a/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
@@ -82,7 +82,7 @@ public class JavaToPythonTests {
     }
 
     @Test
-    public void anonymousClasses() throws Exception {
+    public void anonymousClassesWithoutCapture() throws Exception {
         assertEquals(
             value(42),
             execTestProgram(
@@ -91,6 +91,17 @@ public class JavaToPythonTests {
                 "value",
                 asList()));
     }
+
+    @Test
+    public void lambdasWithoutCapture() throws Exception {
+        assertEquals(
+            value(42),
+            execTestProgram(
+                "lambda",
+                TypeName.of("com.example.Lambda"),
+                "value",
+                asList()));
+    }
     
     private PrimitiveValue execTestProgram(
             String directoryName,
diff --git a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
index 9dfe8b8..1be1abb 100644
--- a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
@@ -175,6 +175,15 @@ public class JavaReaderTests {
             readClasses(generateMethodSource("void",
                 "java.util.function.Supplier<Integer> supplier = () -> { return 42; };")));
     }
+
+    @Test
+    public void lambdaWithInferredArgumentsAndBlockBodyIsReadAsAnonymousClassCreation() {
+        assertEquals(
+            readClasses(generateMethodSource("void",
+                "java.util.function.Function<Integer, Integer> function = x -> x;")),
+            readClasses(generateMethodSource("void",
+                "java.util.function.Function<Integer, Integer> function = (Integer x) -> x;")));
+    }
     
     @Test
     public void argumentIsBoxedIfNecessary() {
diff --git a/src/test/resources/java/lambda/com/example/Lambda.java b/src/test/resources/java/lambda/com/example/Lambda.java
new file mode 100644
index 0000000..be8404e
--- /dev/null
+++ b/src/test/resources/java/lambda/com/example/Lambda.java
@@ -0,0 +1,10 @@
+package com.example;
+
+import java.util.function.Function;
+
+public class Lambda {
+    public static int value() {
+        Function<Integer, Integer> function = value -> value * 2;
+        return function.apply(21);
+    }
+}