Sorry, I don’t understand how. [[boundFunctions]] is not readable from the script itself, only from the UA.
To retreive an element from [[boundFunctions]] you need the original function used to create it. If you’ve recieved an instance to that function, you already have a communication channel, right? Or am I missing something? From: Mark S. Miller Sent: Friday, January 06, 2012 5:53 PM To: François REMY Cc: Brendan Eich ; Andrea Giammarchi ; es-discuss Subject: Re: Improving Function.prototype.bind On Fri, Jan 6, 2012 at 1:29 AM, François REMY <fremycompany_...@yahoo.fr> wrote: Such an implementation would be very slow and not efficient, because searching for a key in the "boundFunctions" weakmap would take time. It can be a polyfill solution but a new implementation need something better. I think the solution would be to create an "invisible" [[boundFunctions]] property for all objects containing a dictionnary<weak<function>, weak<boundFunction>> of already-bound functions on the object. The implementation of bind would then be : - if objToBind is not a reference, create a new boundFunction and return it. - if objToBind.[[boundFunctions]] don't exist, create it. - else, check if it contains a key for functionToBind //when you are processing the dictionnary, remove obsolete entries you may find - if yes, check if the weak reference is alive - if yes, returns the boundFunction - create a new boundFunction and store it into objToBind.[[boundFunctions]] - return the newly created boundFunction Would that be possible? No, for the same reason. The mutable state you hung off this internal property creates an ambient communications channel. François -----Message d'origine----- From: Brendan Eich Sent: Friday, January 06, 2012 2:22 AM To: Andrea Giammarchi Cc: Axel Rauschmayer ; François REMY ; es-discuss Subject: Re: Improving Function.prototype.bind On Jan 5, 2012, at 4:47 PM, Andrea Giammarchi wrote: Guys, by any chance we can go back into the topic? You'll have to polyfill Function.prototype.bind in the current world of pre-ES5 browsers. Why not then go on to wrap it in a memoizing version that uses a WeakMap if available (emulated with strong keys/values array-based implementation if not)? If you need this machinery, it's all doable. If we should evolve a Harmony bind or betterBind based on your experience and others, we can do that. Right now the lack of memoization is not a burning issue, from what I hear. You've raised it, I think for the first time on es-discuss. /be _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss -- Cheers, --MarkM
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