On Jul 16, 2008, at 4:10 PM, Allen Wirfs-Brock wrote: > The most common use case seems to be the one where the target object > is a newly instantiated object without any properties of its own. > That use case (at least for variants of extend that only take a > single source object) is most directly supported by the Object.clone > function in our proposal. However, Object.clone is defined to be a > more comprehensive object duplication process than is performed by > extend. It duplicates all own properties and their attributes and > any internal properties such as its [[Value]] property if it has one.
1) It seems like Object.clone as you have described it is not suitable for the "mixin" type use case where an object gets properties/methods from two others. Or at least, it only does half the job. 2) Is Object.clone expected to work on host objects (in particular DOM- related objects)? I think thorough cloning of all state is not a practical semantic in that case, and would be a very large burden on implementations. In the case of some classes (Window or Location for instance) allowing true cloning might even be a security risk. And if it does not support host objects then copying internal state like the [[Value]] or [[Class]] property for ES standard object types will be more confusing than helpful. Regards, Maciej _______________________________________________ Es4-discuss mailing list Es4-discuss@mozilla.org https://mail.mozilla.org/listinfo/es4-discuss
