On Thu, Sep 25, 2014 at 5:38 PM, Brendan Eich <bren...@mozilla.org> wrote: > On Sep 25, 2014, at 7:56 PM, Boris Zbarsky <bzbar...@mit.edu> wrote: >> >> SpiderMonkey used to support __noSuchMethod__, I believe. > > I implemented __noSuchMethod__ long ago, for the TIBET folks (Smalltalk style > JS framework; they wanted a doesNotUnderstand analogue). > > Please note well the difference between __noSuchMethod__ and anything like > __noSuchProperty__. Even ignoring JITs, back in the interpreter only days, I > could justify nSM because it was called on a slow path, when the only outcome > without it was a guaranteed "obj.foo is not callable" or worse, "obj.foo is > not defined" error. > > IOW nSM only kicked in when evaluating > > obj.foo(args) > > Not just > > obj.foo > > Any nSP of the kind we seem to be discussing would need to fail fast, on > evaluation of the dot expression. That is a fast path.
I, personally, have only ever used Python and PHP's nSP functionality to implement methods. Most of the fancy uses I see for it in, say, Ruby (like the cool dynamic query methods on ORMs), are also methods. There are certainly uses for this kind of functionality for non-method properties, but I suspect just going with noSuchMethod would satisfy most use-cases. I'd certainly be happier with that. ^_^ ~TJ _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
