Simplify generated code for string interpolation by delaying the constant folding.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index dd043571b18514de01a99238aab430ea09c04417..55f0bbabd8a21b56b65c26a32c6b70e68f74b8cd 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -376,17 +376,12 @@ checkGrowable(list, reason) {
   }
 }
 
-String stringToString(value) {
+String S(value) {
   var res = value.toString();
   if (res is !String) throw new IllegalArgumentException(value);
   return res;
 }
 
-String stringConcat(String receiver, String other) {
-  return JS('String', @'# + #', receiver, other);
-}
-
-
 class ListIterator<T> implements Iterator<T> {
   int i;
   List<T> list;
@@ -415,13 +410,10 @@ class Primitives {
   static final int DOLLAR_CHAR_VALUE = 36;
 
   static String objectToString(Object object) {
-    String name = JS('String', @'#.constructor.name', object);
-    if (name === null) {
-      name = JS('String', @'#.match(/^\s*function\s*\$?(\S*)\s*\(/)[1]',
-                JS('String', @'#.constructor.toString()', object));
-    } else {
-      if (name.charCodeAt(0) === DOLLAR_CHAR_VALUE) name = name.substring(1);
-    }
+    String name = getTypeNameOf(object);

[sra1, 2012/06/06 18:07:06]

I think you should use getTypeNameOf only if the object.constructor.name is not
a string.

Regular Dart objects will have a constructor name - the one you arranged for.

The principal purpose of getTypeNameOf is to extract a tag from the object
somehow for native dispatch.
We make it lie for browser compat reasons.
It was never intended to work for general objects, and making it do so will
complicate the native dispatch.
For example, we rename 'Window' to 'DOMWindow', but you may also have another
pure Dart class called Window, and that would get renamed by mistake.

Perhaps we should rename getTypeNameOf to getDispatchTagForNativeClass.

+    // TODO(kasperl): If the namer gave us a fresh global name, we may
+    // want to remove the numeric suffix that makes it unique too.
+    if (name.charCodeAt(0) === DOLLAR_CHAR_VALUE) name = name.substring(1);
     return "Instance of '$name'";
   }