I would welcome (with fanfare and parades) a new Symbol(obj) that worked for strings and integers. Such is not possible using the WeakMap shim (you'd have to detect the type of the value and have multiple dictionaries, or something, and you'd leak the symbols forever...)
Of course, what that means is I'm asking for weakly cached symbols with referential identity, which means it would allow detecting garbage collections, so this is probably around the point where people chime in and say it's not possible. Oh well. :( On Fri, Jul 12, 2013 at 12:42 PM, Jeremy Martin <[email protected]> wrote: > Good point, that's definitely a usable solution (also a better > representation of what I was attempting to describe). > > I'd still be interested in a less-verbose/more-efficient approach using > the Symbol constructor, but it may not be a common enough scenario to > justify it when a workaround does exist. > > > On Fri, Jul 12, 2013 at 3:32 PM, Allen Wirfs-Brock > <[email protected]>wrote: > >> >> On Jul 12, 2013, at 12:14 PM, Jeremy Martin wrote: >> >> In brief: allow Symbol's to be constructed with a single parameter, with >> the following behavior: >> >> > var obj = {}; >> undefined >> > new Symbol({}) === new Symbol({}) >> false >> > new Symbol(obj) === new Symbol(obj) >> true >> >> >> You can use a WeakMap to build your own object-selected Symbol factory: >> >> let known = new WeakMap; >> >> function ObjSymFactory(obj) { >> //handle obj === undefined however you want >> let sym = known.get(obj); >> If (!sym) { >> sym = new Symbol; >> known.set(obj,sym); >> } >> return sym; >> } >> >> Allen >> >> >> > > > -- > Jeremy Martin > 661.312.3853 > http://devsmash.com > @jmar777 > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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