What struck me from Jeremy's explanation was the uniformity of CoffeeScript's ? operator (modulo the small issue he mentioned for function calls). It seems to combine the currently-strawman'ed ??/??= and ?. into one very simple semantic.
What about adopting ?? as CoffeeScript's ? operator? Would this solve the lookahead problems? So you could do object.property??.other.properties.go.here object.method??(args) This would unfortunately imply, for uniformity, that object ?? other object ??= other become null + undefined tests instead of just undefined. But that might be worth paying. For the record that leaves object?? as the only unimplemented CoffeeScript counterpart. ________________________________________ From: es-discuss-boun...@mozilla.org [es-discuss-boun...@mozilla.org] on behalf of Brendan Eich [bren...@mozilla.org] Sent: Tuesday, June 19, 2012 14:08 To: Jeremy Ashkenas Cc: es-discuss Subject: Re: Existential operator (was: ||= is much needed?) Jeremy Ashkenas wrote: > > Everywhere else in the language, `?` means existence (not null or > undefined) -- but when used to call a function, the check ensures that > the value is callable as well. In a DWIM sense, this makes sense, > because the only things you'd ever want to try to call in JavaScript > must be callable ... but I think it's strange that the meaning of > "existence" alters itself just for this use case. I opened a ticket > talking about rolling it back to "null or undefined" semantics here: > > https://github.com/jashkenas/coffee-script/issues/2315 Apart from people misreading the proposal in this issue, it does seem to be removing a bit of utility, but perhaps that's not actually used? Do CS users try to ?(-invoke a maybe-function that is sometimes neither null nor undefined nor typeof-type "function", but rather something that coerces to object? The way to get ?( into JS is by a longer spelling: options.success?.(response) Pretty ugly, but it puts the ? magic right where the maybe-test belongs. /be _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
