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 211 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 #$nameOrPosition is not an Identifier'
+        return error('Interpolated value #$nameOrPosition ($item: ${item?.runtimeType}) is not an Identifier'

[Jennifer Messerly, 2015/12/01 02:10:27]

long line.

also, printing the item & runtime type isn't a bad idea for debugging, but if
we're going to do it here, why not in all the other places?

I'd say keep it consistent one way or the other. (e.g. add a helper if
item/runtimeType is desired, and call it from all of the interpolation
places...)

[ochafik, 2015/12/02 20:05:47]

Done.

                      ' or List of Identifiers: $value');
       }
       if (value is Iterable) return value.map(toIdentifier);
       return toIdentifier(value);
     };
   }
 
   Instantiator visitInterpolatedSelector(InterpolatedSelector node) {
     // A selector is an expression, as in `a[selector]`.
     // A String argument converted into a LiteralString, so `a.#` with argument
@@ skipping 571 matching lines @@
       return new CommentExpression(node.comment, makeExpr(arguments));
     };
   }
 
   Instantiator visitAwait(Await node) {
     Instantiator makeExpression = visit(node.expression);
     return (arguments) {
       return new Await(makeExpression(arguments));
     };
   }
+
+  @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(
+          makeName(arguments),
+          makeStructure(arguments),
+          makeDefaultValue(arguments));
+    };
+  }
+
+  @override
+  Instantiator visitArrayDestructuring(ArrayDestructuring node) {
+    List<Instantiator> makeVars = node.variables.map(this.visit).toList();
+    return (arguments) {
+      return new ArrayDestructuring(makeVars.map((m) => m(arguments)).toList());
+    };
+  }
+
+  @override
+  Instantiator visitObjectDestructuring(ObjectDestructuring node) {
+    List<Instantiator> makeVars = node.variables.map(this.visit).toList();
+    return (arguments) {
+      return new ObjectDestructuring(makeVars.map((m) => m(arguments)).toList());

[Jennifer Messerly, 2015/12/01 02:10:28]

long line

[ochafik, 2015/12/02 20:05:47]

Done.

+    };
+  }
 }
 
 /**
  * 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;
   }
 }