Support named arguments for dynamic calls.

frog/leg/emitter.dart

Index: frog/leg/emitter.dart
===================================================================
--- frog/leg/emitter.dart	(revision 3778)
+++ frog/leg/emitter.dart	(working copy)
@@ -41,26 +41,58 @@
                         String prototype,
                         StringBuffer buffer,
                         Invocation invocation) {
-    // TODO(ngeoffray): also support invocation with names.
+    FunctionParameters parameters = member.computeParameters(compiler);
+    int positionalArgumentCount = invocation.positionalArgumentCount;
+    if (positionalArgumentCount == parameters.parameterCount) return;
+    List<SourceString> names = invocation.orderedNamedArguments;
+    assert(names.length == invocation.namedArguments.length);
+
     String invocationName =
-        namer.instanceMethodName(member.name, invocation.argumentCount);
-    int allParameters = member.parameterCount(compiler);
-    int missingParameters = allParameters - invocation.argumentCount;
-    if (missingParameters == 0) return;
-    assert(missingParameters > 0);
+        namer.instanceMethodInvocationName(member.name, invocation);
     buffer.add('$prototype.$invocationName = function(');
-    StringBuffer parameters = new StringBuffer();
-    for (int i = 0; i < invocation.argumentCount; i++) {
-      if (i != 0) parameters.add(', ');
-      parameters.add('param$i');
+
+    // The parameters that this stub takes.

[kasperl, 2012/02/01 10:21:21]

Maybe you could write a comment with a few examples that illustrate how this
works?

[ngeoffray, 2012/02/01 11:44:15]

Done.

+    StringBuffer parametersBuffer = new StringBuffer();
+    // The missing and named arguments that will be passed to the real
+    // method.
+    StringBuffer missingAndNamedArgumentsBuffer = new StringBuffer();
+    StringBuffer positionalArgumentsBuffer = new StringBuffer();
+
+    int count = 0;
+    parameters.forEachParameter((Element element) {
+      if (count < positionalArgumentCount) {
+        if (count != 0) parametersBuffer.add(', ');
+        parametersBuffer.add('${element.name}');
+        positionalArgumentsBuffer.add('${element.name}');
+      } else {
+        if (count != positionalArgumentCount || positionalArgumentCount != 0) {
+          missingAndNamedArgumentsBuffer.add(', ');
+        }
+        int index = names.indexOf(element.name);
+        if (index != -1) {
+          // The order of the named arguments is not the same as the
+          // one in the real method (which is in Dart source order).
+          // Therefore, we don't add the argument to the
+          // [parametersBuffer] just yet.
+          missingAndNamedArgumentsBuffer.add('${element.name}');
+        } else {
+          // TODO(ngeoffray): Get the default value.
+          missingAndNamedArgumentsBuffer.add('(void 0)');
+        }
+      }
+      count++;
+    });
+
+    // Add the named arguments to the parametersBuffer.
+    for (SourceString name in names) {
+      if (positionalArgumentCount != 0) parametersBuffer.add(', ');
+      parametersBuffer.add(name);
     }
-    buffer.add('$parameters) {\n');
-    buffer.add('  this.${namer.getName(member)}($parameters');
-    for (int i = 0; i < missingParameters; i++) {
-      if (i != 0 || invocation.argumentCount != 0) buffer.add(', ');
-      buffer.add('(void 0)');
-    }
-    buffer.add(')\n}\n');
+
+    buffer.add('$parametersBuffer) {\n');
+    buffer.add('  return this.${namer.getName(member)}');
+    buffer.add('($positionalArgumentsBuffer$missingAndNamedArgumentsBuffer)');
+    buffer.add('\n}\n');
   }
 
   void addParameterStubs(FunctionElement member,