Use destructuring assignments for named parameters (#180)

lib/src/js/template.dart

Index: lib/src/js/template.dart
diff --git a/lib/src/js/template.dart b/lib/src/js/template.dart
index d376c45e136b54ebc58c77366bdb90a63b931d72..addc3327abf8f5af0cb113214b072d6e80610ce0 100644
--- a/lib/src/js/template.dart
+++ b/lib/src/js/template.dart
@@ -229,10 +229,10 @@ class InstantiatorGeneratorVisitor implements NodeVisitor<Instantiator> {
     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);
@@ -824,6 +824,35 @@ class InstantiatorGeneratorVisitor implements NodeVisitor<Instantiator> {
       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.

+    };
+  }
 }
 
 /**