As there is no keyword as 'or' so far, does something like *x = x.value or 5 *sound better?
On Tue, Jun 19, 2012 at 3:00 PM, David Bruant <[email protected]> wrote: > What about a more generic operator that would be able to silently absorb > any error? > > let greedy = obj.hints?.greedy; > > would become: > > let greedy = silent obj.hints.greedy; > > The semantic would be exactly the same. > The syntax is up to debate. Specifically, it would be nice to be able to > silence a part of an expression. > What about a 'try' without a catch? > > let greedy = try obj.hints.greedy > let greedy = try{ obj.hints.greedy } || 22; > > This is currently forbidden (I think for 2 reasons, one being that a try > must be followed by a catch or finally and the other that try/catch cannot > be used as expressions) > > This idea is partly inspired by typeof which silences ReferenceErrors, > which I see as a feature YMMV. > It is also intended to make programs potentially more robust more easily. > For instance, JSON.stringify can throw errors in the rare case of cyclic > references. But very few people know that. To make a robust program using > JSON.stringify, one would just need to turn: > > let s = JSON.stringify(o) > > into > > let s = try{ JSON.stringify(o) } || DEFAULT_VALUE; > > instead of the current: > > let s; > try{ > s = JSON.stringify(o) > } > catch(e){ > // I don't care about the error anyway > s = DEFAULT_VALUE; > } > > David > > > Le 18/06/2012 07:11, Brendan Eich a écrit : > >> Sorry, meant to start a new thread for: >> >> >> http://wiki.ecmascript.org/**doku.php?id=strawman:**existential_operator<http://wiki.ecmascript.org/doku.php?id=strawman:existential_operator> >> >> As the Syntax section hints, we can't also adopt CoffeeScript's ?( >> variant, which enables foo.bar?(args, go, here).baz and the like. The C >> syntax heritage prevails. >> >> /be >> >> Brendan Eich wrote: >> >>> David Herman wrote: >>> >>>> On Jun 15, 2012, at 5:57 PM, satyr wrote: >>>> >>>> On Sat, Jun 16, 2012 at 4:33 AM, David Herman <[email protected]<mailto: >>>>> [email protected]>> wrote: >>>>> >>>>> As for null, I can see how there's confusion about whether to use >>>>> null vs undefined, and so I can see why CoffeeScript would just >>>>> try to blur the distinction between them. >>>>> >>>>> >>>>> Not just for blurring. Rejecting `null` is essential for >>>>> CoffeeScript's "existence" due to `?.`, the soak/safe access operator. >>>>> >>>> >>>> I think you could make a case for ?. defaulting for both but ?? >>>> defaulting only undefined. The case goes something like this: >>>> >>>> - The purpose of ?? is to provide a default value when no value was >>>> provided. The way to say "no value" in JavaScript is undefined. >>>> >>>> - The purpose of ?. is to fail soft when doing a property lookup. Both >>>> null and undefined throw when doing a property lookup. >>>> >>> >>> Agreed. This is one choice, it's plausible because of the distinction >>> between defaulting (which requires intentional passing of a "please >>> default" sentinel value, or not passing a trailing actual argument) and >>> soaking up null-or-undefined. >>> >>> Yes, we could make ?? and ??= do the same for null as for undefined. I'm >>> not sure that's the right choice, but it's a choice. For foo.bar?.baz, >>> though, the clearer choice is to avoid throwing, which means evaluating to >>> undefined if foo.bar is missing (evaluates to undefined) *or* has a value >>> not coercible to object type (null or undefined). See >>> >>> http://wiki.ecmascript.org/**doku.php?id=strawman:**existential_operator<http://wiki.ecmascript.org/doku.php?id=strawman:existential_operator> >>> >>> /be >>> ______________________________**_________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/**listinfo/es-discuss<https://mail.mozilla.org/listinfo/es-discuss> >>> >>> ______________________________**_________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/**listinfo/es-discuss<https://mail.mozilla.org/listinfo/es-discuss> >> > > ______________________________**_________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/**listinfo/es-discuss<https://mail.mozilla.org/listinfo/es-discuss> > -- *'I am what I am because of who we all are'* h3manth.com <http://www.h3manth.com> *-- Hemanth HM *
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