const constructors with optional arguments.

frog/leg/compile_time_constants.dart

Index: frog/leg/compile_time_constants.dart
diff --git a/frog/leg/compile_time_constants.dart b/frog/leg/compile_time_constants.dart
index cefe2f5f2a70f8d0f44862a181f09597555c33cf..5ac826a602db0f8f5350ace77a2399e441c60bdc 100644
--- a/frog/leg/compile_time_constants.dart
+++ b/frog/leg/compile_time_constants.dart
@@ -900,36 +900,23 @@ class CompileTimeConstantEvaluator extends AbstractVisitor {
   }
 
   Constant visitNewExpression(NewExpression node) {
-    List<Constant> compileArguments() {
-      if (!node.isConst()) error(node);
-      Send send = node.send;
-      List<Constant> arguments;
-      if (send.arguments.isEmpty()) {
-        arguments = const <Constant>[];
-      } else {
-        arguments = <Constant>[];
-        for (Link<Node> link = send.arguments;
-             !link.isEmpty();
-             link = link.tail) {
-          arguments.add(evaluate(link.head));
-        }
-      }
-      return arguments;
-    }
-
     void assignArgumentsToParameters(
-        List<Constant> arguments,
         FunctionParameters parameters,
         Map<Element, Constant> constructorDefinitions) {
-      if (arguments.length != parameters.parameterCount) {
-        if (arguments.length < parameters.parameterCount &&
-            arguments.length >= parameters.requiredParameterCount) {
-          compiler.unimplemented("ConstantHandler with optional arguments",
-                                 node: node);
-        } else {
-          error(node);
-        }
-      }
+      Send send = node.send;
+      if (send.arguments.isEmpty() && parameters.parameterCount == 0) return;
+      List<Constant> arguments = <Constant>[];
+      Selector selector = elements.getSelector(send);
+
+      Constant evaluateConstant(Element element)
+          => constantHandler.compileVariable(element);
+
+      Function visitArgument = evaluate;
+      Function visitConstant = constantHandler.compileVariable;

[ngeoffray, 2012/03/15 10:24:58]

Because this class is a visitor, I'd prefer avoiding the name 'visit'. Also, you
could drop evaluateConstant, visitArgument and visitConstant and pass the
functions directly to addSendArgumentsToList.

[floitsch, 2012/03/15 14:30:47]

removed evaluateConstant (old dead code).
renamed visit{Argument|Constant} to compile{Argument|Constant} and changed the
name of the parameters in addSendArgumentsToList.

+      bool succeeded = selector.addSendArgumentsToList(
+          send, arguments, parameters, visitArgument, visitConstant);
+      if (!succeeded) error(node);
+
       int index = 0;
       parameters.forEachParameter((Element parameter) {
         constructorDefinitions[parameter] = arguments[index++];
@@ -980,6 +967,8 @@ class CompileTimeConstantEvaluator extends AbstractVisitor {
       return fieldValues;
     }
 
+    if (!node.isConst()) error(node);
+
     // TODO(floitsch): get the type from somewhere.
     FunctionElement constructor = elements[node.send];
     ClassElement classElement = constructor.enclosingElement;
@@ -992,8 +981,7 @@ class CompileTimeConstantEvaluator extends AbstractVisitor {
     Map<Element, Constant> constructorDefinitions =
         new Map<Element, Constant>();
 
-    List<Constant> arguments = compileArguments();
-    assignArgumentsToParameters(arguments, parameters, constructorDefinitions);
+    assignArgumentsToParameters(parameters, constructorDefinitions);
     CompileTimeConstantEvaluator initializerEvaluator =
         new CompileTimeConstantEvaluator.insideConstructor(
             constantHandler, constructorElements, compiler,