[pkg:polymer] add support for bool/int/double/String attributes

lib/polymer_element.dart

 // Copyright (c) 2013, 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.
 
 library polymer.polymer_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:mirrors';
 
@@ skipping 99 matching lines @@
         name = name.trim();
 
         // TODO(jmesserly): PathObserver is overkill here; it helps avoid
         // "new Symbol" and other mirrors-related warnings.
         _publishedAttrs[name] = new PathObserver(this, toCamelCase(name));
       }
     }
   }
 
   void created() {
-    // TODO(jmesserly): this breaks until we get some kind of type conversion.
-    // _publishedAttrs.forEach((name, propObserver) {
-    // var value = attributes[name];
-    //   if (value != null) propObserver.value = value;
-    // });
+    _publishedAttrs.forEach((name, propObserver) {
+      var oldValue = propObserver.value;
+      if (oldValue is bool) {
+        propObserver.value = attributes.containsKey(name);
+        return;
+      }
+      var value = attributes[name];
+      if (value == null) return;
+
+      if (oldValue is int) {
+        propObserver.value = int.parse(value, onError: (x) => null);

[Siggi Cherem (dart-lang), 2013/08/06 16:40:39]

should we assign onError or just skip setting the property altogether?

[Jennifer Messerly, 2013/08/06 16:44:23]

good question. I figured setting to "null" would signal an invalid value. But
not setting is consistent with some of the error-tolerant HTML behavior. I'll
need to do more research on this

[Jennifer Messerly, 2013/08/06 20:04:52]

hmm, Polymer source code is not helpful in this case. If they fail to parse,
they let it become a string:

https://github.com/Polymer/polymer/blob/master/src/lib/deserialize.js#L24

that would most likely cause a checked mode error in Dart, which would leave the
original value.

input type=number will give you a NaN if "value" attribute is invalid, but
that's also the default.

based on that, I'm inclined to switch it to your suggestion of preserving the
original value.

+      } else if (oldValue is double) {
+        propObserver.value = double.parse(value, (x) => null);
+      } else {
+        //  Assume it's a string.
+        propObserver.value = value;

[Siggi Cherem (dart-lang), 2013/08/06 16:40:39]

how about:
propObserver.value = value.toString();
?

[Jennifer Messerly, 2013/08/06 16:44:23]

value will always be a string because it comes from attributes:
http://api.dartlang.org/docs/releases/latest/dart_html/Element.html#attributes

[Siggi Cherem (dart-lang), 2013/08/06 16:46:01]

Ah, <facepalm>, makes sense. thx

+      }
+    });
     _initShadowRoot();
     _addHostListeners();
   }
 
   /**
    * Creates the document fragment to use for each instance of the custom
    * element, given the `<template>` node. By default this is equivalent to:
    *
    *     template.createInstance(this, fancySyntax);
    *
@@ skipping 381 matching lines @@
   'onKeyMessage': MediaElement.keyMessageEvent,
   'onNeedKey': MediaElement.needKeyEvent,
   'onWebGlContextLost': CanvasElement.webGlContextLostEvent,
   'onWebGlContextRestored': CanvasElement.webGlContextRestoredEvent,
   'onPointerLockChange': Document.pointerLockChangeEvent,
   'onPointerLockError': Document.pointerLockErrorEvent,
   'onReadyStateChange': Document.readyStateChangeEvent,
   'onSelectionChange': Document.selectionChangeEvent,
   'onSecurityPolicyViolation': Document.securityPolicyViolationEvent,
 };