Custom Syntax's are now enabled via template.bindingDelegate =

tools/dom/templates/html/impl/impl_Element.darttemplate

 // Copyright (c) 2012, 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 $LIBRARYNAME;
 
 class _ChildrenElementList extends ListBase<Element> {
   // Raw Element.
   final Element _element;
   final HtmlCollection _childElements;
@@ skipping 844 matching lines @@
    * Gets the content of this template.
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
   DocumentFragment get content {
     _ensureTemplate();
     return _templateContent;
   }
 
   /**
-   * Creates an instance of the template.
+   * Creates an instance of the template, using the provided model and binding
+   * delegate.
+   *
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
-  DocumentFragment createInstance(model, String syntax) {
+  DocumentFragment createInstance(model, BindingDelegate delegate) {
     _ensureTemplate();
-    return TemplateElement.mdvPackage(this).createInstance(model, syntax);
+    return TemplateElement.mdvPackage(this).createInstance(model, delegate);
   }
 
   /**
    * The data model which is inherited through the tree.
    * This is only supported if [isTemplate] is true.
    */
   @Experimental()
   get model => TemplateElement.mdvPackage(this).model;
 
   @Experimental()
   void set model(value) {
     _ensureTemplate();
     TemplateElement.mdvPackage(this).model = value;
   }
 
+  /**
+   * The binding delegate which is inherited through the tree. It can be used
+   * to configure custom syntax for `{{bindings}}` inside this template.
+   *
+   * This is only supported if [isTemplate] is true.
+   */
+  @Experimental()
+  BindingDelegate get bindingDelegate =>
+      TemplateElement.mdvPackage(this).bindingDelegate;
+
+  @Experimental()
+  void set bindingDelegate(BindingDelegate value) {
+    _ensureTemplate();
+    TemplateElement.mdvPackage(this).bindingDelegate = value;
+  }
+
   // TODO(jmesserly): const set would be better
   static const _TABLE_TAGS = const {
     'caption': null,
     'col': null,
     'colgroup': null,
     'tbody': null,
     'td': null,
     'tfoot': null,
     'th': null,
     'thead': null,
@@ skipping 167 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }