mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
01bec1736f
function, rename it _init(), plumb that through AutomaticMetadata, and move @tagname and Element.tagname to a new frameworks.md file that has stuff that wouldn't actually be part of core Sky Review URL: https://codereview.chromium.org/946513006
1.1 KiB
1.1 KiB
Frameworks
Sky is intended to support multiple frameworks. Here is one way you could register a custom element using Dart annotations:
// @tagname annotation for registering elements
// only useful when placed on classes that inherit from Element
class tagname extends AutomaticMetadata {
const tagname(this.name);
final String name;
void init(DeclarationMirror target, Module module, ScriptElement script) {
assert(target is ClassMirror);
if (!(target as ClassMirror).isSubclassOf(reflectClass(Element)))
throw new UnsupportedError('@tagname can only be used on descendants of Element');
module.registerElement(name, (target as ClassMirror).reflectedType);
}
}
A framework that used the above code could use the following code to get the tag name of an element:
String getTagName(Element element) { // O(N) in number of annotations on the class
// throws a StateError if the class doesn't have an @tagname annotation
var tagnameClass = reflectClass(tagname);
return (reflectClass(element.runtimeType).metadata.singleWhere((mirror) => mirror.type == tagnameClass).reflectee as tagname).name;
}