Use destructuring assignments for named parameters (#180)

lib/src/js/template.dart

 // Copyright (c) 2014, 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.
 
 part of js_ast;
 
 class TemplateManager {
   Map<String, Template> expressionTemplates = new Map<String, Template>();
   Map<String, Template> statementTemplates = new Map<String, Template>();
 
@@ skipping 212 matching lines @@
       if (value is Literal) return value;
       error('Interpolated value #$nameOrPosition is not a Literal: $value');
     };
   }
 
   Instantiator visitInterpolatedParameter(InterpolatedParameter node) {
     var nameOrPosition = node.nameOrPosition;
     return (arguments) {
       var value = arguments[nameOrPosition];
 
-      Identifier toIdentifier(item) {
-        if (item is Identifier) return item;
+      Parameter toIdentifier(item) {
+        if (item is Parameter) return item;
         if (item is String) return new Identifier(item);
         return error('Interpolated value #$nameOrPosition is not an Identifier'
             ' or List of Identifiers: $value');
       }
       if (value is Iterable) return value.map(toIdentifier);
       return toIdentifier(value);
     };
   }
 
   Instantiator visitInterpolatedSelector(InterpolatedSelector node) {
@@ skipping 574 matching lines @@
       throw new UnimplementedError();
 
   Instantiator visitImportDeclaration(ImportDeclaration node) =>
       throw new UnimplementedError();
 
   Instantiator visitExportDeclaration(ExportDeclaration node) =>
       throw new UnimplementedError();
 
   Instantiator visitExportClause(ExportClause node) =>
       throw new UnimplementedError();
+
+  @override
+  Instantiator visitDestructuredVariable(DestructuredVariable node) {
+    Instantiator makeName = visit(node.name);
+    Instantiator makeStructure = visit(node.structure);
+    Instantiator makeDefaultValue = visit(node.defaultValue);
+    return (arguments) {
+      return new DestructuredVariable(
+          name: makeName(arguments),
+          structure: makeStructure(arguments),
+          defaultValue: makeDefaultValue(arguments));
+    };
+  }
+
+  @override
+  Instantiator visitArrayBindingPattern(ArrayBindingPattern node) {
+    List<Instantiator> makeVars = node.variables.map(this.visit).toList();
+    return (arguments) {
+      return new ArrayBindingPattern(
+          makeVars.map((m) => m(arguments)).toList());
+    };
+  }
+
+  @override
+  Instantiator visitObjectBindingPattern(ObjectBindingPattern node) {
+    List<Instantiator> makeVars = node.variables.map(this.visit).toList();
+    return (arguments) {
+      return new ObjectBindingPattern(
+          makeVars.map((m) => m(arguments)).toList());
+    };
+  }
 }
 
 /**
  * InterpolatedNodeAnalysis determines which AST trees contain
  * [InterpolatedNode]s, and the names of the named interpolated nodes.
  */
 class InterpolatedNodeAnalysis extends BaseVisitor {
   final Set<Node> containsInterpolatedNode = new Set<Node>();
   final Set<String> holeNames = new Set<String>();
   int count = 0;
@@ skipping 13 matching lines @@
     if (count != before) containsInterpolatedNode.add(node);
     return null;
   }
 
   visitInterpolatedNode(InterpolatedNode node) {
     containsInterpolatedNode.add(node);
     if (node.isNamed) holeNames.add(node.nameOrPosition);
     ++count;
   }
 }