[] for collections

idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -1472,14 +1472,27 @@ public class ExpressionCodegen extends JetVisitor {
     public void visitArrayAccessExpression(JetArrayAccessExpression expression) {
         final JetExpression array = expression.getArrayExpression();
         final Type arrayType = expressionType(array);
+        gen(array, arrayType);
+        generateArrayIndex(expression);
         if (arrayType.getSort() == Type.ARRAY) {
-            gen(array, arrayType);
-            generateArrayIndex(expression);
             final Type elementType = arrayType.getElementType();
             myStack.push(StackValue.arrayElement(elementType));
         }
         else {
-            throw new UnsupportedOperationException("array access to non-Java arrays is not supported");
+            final PsiElement declaration = bindingContext.resolveToDeclarationPsiElement(expression);
+            final CallableMethod accessor;
+            if (declaration instanceof PsiMethod) {
+                accessor = JetTypeMapper.mapToCallableMethod((PsiMethod) declaration);
+            }
+            else if (declaration instanceof JetNamedFunction) {
+                accessor = typeMapper.mapToCallableMethod((JetNamedFunction) declaration);
+            }
+            else {
+                throw new UnsupportedOperationException("unknown accessor type");
+            }
+            boolean isGetter = accessor.getSignature().getName().equals("get");
+            myStack.push(StackValue.collectionElement(JetTypeMapper.TYPE_OBJECT, isGetter ? accessor : null,
+                                                      isGetter ? null : accessor));
         }
     }
 

idea/src/org/jetbrains/jet/codegen/StackValue.java

@@ -67,6 +67,10 @@ public abstract class StackValue {
         return new ArrayElement(type);
     }
 
+    public static StackValue collectionElement(Type type, CallableMethod getter, CallableMethod setter) {
+        return new CollectionElement(type, getter, setter);
+    }
+
     public static StackValue field(Type type, String owner, String name, boolean isStatic) {
         return new Field(type, owner, name, isStatic);
     }
@@ -383,6 +387,43 @@ public abstract class StackValue {
         }
     }
 
+    private static class CollectionElement extends StackValue {
+        private final CallableMethod getter;
+        private final CallableMethod setter;
+
+        public CollectionElement(Type type, CallableMethod getter, CallableMethod setter) {
+            super(type);
+            this.getter = getter;
+            this.setter = setter;
+        }
+
+        @Override
+        public void put(Type type, InstructionAdapter v) {
+            if (getter == null) {
+                throw new UnsupportedOperationException("no getter specified");
+            }
+            getter.invoke(v);
+        }
+
+        @Override
+        public void store(InstructionAdapter v) {
+            if (setter == null) {
+                throw new UnsupportedOperationException("no setter specified");
+            }
+            setter.invoke(v);
+        }
+
+        @Override
+        public void dupReceiver(InstructionAdapter v, int below) {
+            if (below == 1) {
+                v.dup2X1();
+            }
+            else {
+                v.dup2();   // collection and index
+            }
+        }
+    }
+
 
     private static class Field extends StackValue {
         private final String owner;

idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java

@@ -426,4 +426,13 @@ public class NamespaceGenTest extends CodegenTestCase {
         main.invoke(null, list);
         assertEquals("foo", list.get(0));
     }
+
+    public void testArrayAccessForArrayList() throws Exception {
+        loadText("import java.util.*; fun foo(l: ArrayList<String>) { l[0] = \"Jet\" + l[0]; }");
+        final Method main = generateFunction();
+        final ArrayList<String> list = new ArrayList<String>();
+        list.add("Language");
+        main.invoke(null, list);
+        assertEquals("JetLanguage", list.get(0));
+    }
 }