cleanup to Value - fix for StringEscapesTest

frog/library.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class LibraryImport {
   String prefix;
   Library library;
   LibraryImport(this.library, [this.prefix = null]);
 }
 
@@ skipping 444 matching lines @@
     }
     // Even though the collection has one arg, this is the easiest way to get
     // the first item.
     for (var arg in args) {
       return _parseStringArgument(arg);
     }
   }
 
   String _parseStringArgument(ArgumentNode arg) {
     var expr = arg.value;
-    if (expr is! LiteralExpression || !expr.type.type.isString) {
-      world.error('expected string', expr.span);
+    if (expr is! LiteralExpression || !expr.value.type.isString) {
+      world.error('expected string literal', expr.span);
     }
-    return parseStringLiteral(expr.value);
+    return expr.value.actualValue;
   }
 
   void visitTypeDefinition(TypeDefinition node) {
     var oldType = currentType;
     currentType = library.addType(node.name.name, node, node.isClass);
     for (var member in node.body) {
       member.visit(this);
     }
     currentType = oldType;
   }
 
   void visitVariableDefinition(VariableDefinition node) {
     currentType.addField(node);
   }
 
   void visitFunctionDefinition(FunctionDefinition node) {
     currentType.addMethod(node.name.name, node);
   }
 
   void visitFunctionTypeDefinition(FunctionTypeDefinition node) {
     var type = library.addType(node.func.name.name, node, false);
     type.addMethod(':call', node.func);
   }
 }