Support assignments with operations

4 files changed, 59 insertions, 8 deletions

diff --git a/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
index 9ad750b..371ec2d 100644
--- a/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
+++ b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
@@ -39,7 +39,7 @@ public class MethodCallNode implements ExpressionNode {
         return integerOperation(Operator.MOD.getMethodName(), left, right);
     }
 
-    private static MethodCallNode integerOperation(String methodName, ExpressionNode left, ExpressionNode right) {
+    public static MethodCallNode integerOperation(String methodName, ExpressionNode left, ExpressionNode right) {
         return methodCall(left, methodName, asList(right), IntegerValue.REF);
     }
 
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 941c50e..bf66092 100644
--- a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
+++ b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
@@ -17,7 +17,6 @@ import static java.util.Arrays.asList;
 import static org.zwobble.couscous.ast.ExpressionStatementNode.expressionStatement;
 import static org.zwobble.couscous.ast.LiteralNode.literal;
 import static org.zwobble.couscous.ast.LocalVariableDeclarationNode.localVariableDeclaration;
-import static org.zwobble.couscous.ast.MethodCallNode.methodCall;
 import static org.zwobble.couscous.ast.VariableDeclaration.var;
 import static org.zwobble.couscous.ast.VariableReferenceNode.reference;
 import static org.zwobble.couscous.ast.WhileNode.whileLoop;
@@ -397,12 +396,39 @@ public class JavaReader {
     }
     
     private static ExpressionNode readAssignment(Assignment expression) {
-        ExpressionNode left = readExpressionWithoutBoxing(expression.getLeftHandSide());
-        return AssignmentNode.assign(
-            (AssignableExpressionNode)left,
-            readExpression(left.getType(), expression.getRightHandSide()));
+        // TODO: fix boxing
+        AssignableExpressionNode left = (AssignableExpressionNode)readExpressionWithoutBoxing(expression.getLeftHandSide());
+        ExpressionNode right = readExpression(left.getType(), expression.getRightHandSide());
+        if (expression.getOperator() == Assignment.Operator.ASSIGN) {
+            return AssignmentNode.assign(left, right);
+        } else {
+            Operator operator = readOperator(expression.getOperator());
+            return AssignmentNode.assign(
+                left,
+                MethodCallNode.methodCall(
+                    left,
+                    operator.getMethodName(),
+                    asList(right),
+                    left.getType()));
+        }
     }
-    
+
+    private static Operator readOperator(Assignment.Operator operator) {
+        if (operator == Assignment.Operator.PLUS_ASSIGN) {
+            return Operator.ADD;
+        } else if (operator == Assignment.Operator.MINUS_ASSIGN) {
+            return Operator.SUBTRACT;
+        } else if (operator == Assignment.Operator.TIMES_ASSIGN) {
+            return Operator.MULTIPLY;
+        } else if (operator == Assignment.Operator.DIVIDE_ASSIGN) {
+            return Operator.DIVIDE;
+        } else if (operator == Assignment.Operator.REMAINDER_ASSIGN) {
+            return Operator.MOD;
+        } else {
+            throw new RuntimeException("Unrecognised operator: " + operator);
+        }
+    }
+
     private static String generateClassName(CompilationUnit ast) {
         TypeDeclaration type = (TypeDeclaration)ast.types().get(0);
         return ast.getPackage().getName().getFullyQualifiedName() + "." + type.getName().getFullyQualifiedName();
diff --git a/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java b/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
index fa6322f..f17f42b 100644
--- a/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/JavaToPythonTests.java
@@ -60,7 +60,6 @@ public class JavaToPythonTests {
     }
 
     @Test
-    @Ignore("WIP")
     public void whileFactorial() throws Exception {
         assertEquals(
             value(720),
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 3f06f49..6f116cc 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
@@ -354,6 +354,32 @@ public class JavaReaderTests {
     }
 
     @Test
+    public void canReadCompoundAssignmentOperations() {
+        canReadCompoundAssignmentOperation("+=", Operator.ADD);
+        canReadCompoundAssignmentOperation("-=", Operator.SUBTRACT);
+        canReadCompoundAssignmentOperation("*=", Operator.MULTIPLY);
+        canReadCompoundAssignmentOperation("/=", Operator.DIVIDE);
+        canReadCompoundAssignmentOperation("%=", Operator.MOD);
+    }
+
+    private void canReadCompoundAssignmentOperation(String symbol, Operator operator) {
+        ClassNode classNode = readClass(
+            "public void go(int value) {" +
+            "    value " + symbol + " 2;" +
+            "}");
+
+        MethodNode method = classNode.getMethods().get(0);
+        FormalArgumentNode argument = method.getArguments().get(0);
+        ExpressionStatementNode statement = (ExpressionStatementNode)
+            classNode.getMethods().get(0).getBody().get(0);
+        assertEquals(
+            assign(
+                reference(argument),
+                integerOperation(operator.getMethodName(), reference(argument), literal(2))),
+            statement.getExpression());
+    }
+
+    @Test
     public void canReadPrefixDecrement() {
         ClassNode classNode = readClass(
             "public void go(int value) {" +