Here is a proof of concept using Proxy (Spidermonkey only) http://jsbin.com/AWIs/2/edit
It rewrites the `with (expr)` with `with (createUnscopeable(expr))` where createUnscopeable returns a proxy that filters out the black listed property names. On Wed, Aug 21, 2013 at 9:42 AM, Andreas Rossberg <[email protected]> wrote: > On 21 August 2013 15:18, Peter van der Zee <[email protected]> wrote: >> Can somebody (private mail is okay) please clarify this for me? It looks me >> like there's a proposal to introduce `@@` syntax to support something that's >> forbidden in most es6 code anyways (`with`)? Or does it have other use >> cases? Where can I read more about this? > > It's a proposed backwards compatibility thing to work around the > problem that uses of 'with' in the wild are not robust against > extensions of standard objects, see Section 4.3 of the July 23 meeting > notes: > > https://github.com/rwaldron/tc39-notes/blob/master/es6/2013-07/july-23.md > > Unfortunately, many people still use 'with', and we can't break the web. > > (The @@-syntax is just a placeholder we got into the habit of using to > denote predefined symbols.) > > /Andreas > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss -- erik _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
