||= is much needed?

[Aymeric Vitte]

Typo below, I meant "which can be written : if 
(!(((typeof(api)!="undefined"??api.a:undefined)??api.a.b:undefined)??api.a.b.c:undefined)) 
{try later}"

Le 13/06/2012 12:12, Aymeric Vitte a écrit :
> Indeed, maybe both should be included.
>
> What about this case :
>
> if (typeof(api)=="undefined") {try later} else if (!api.a) {try later} 
> else if (!api.a.b)) {try later} else if (etc...)
>
> which can be written : if 
> (!(((typeof(api)!="undefined"?api.a:undefined)?api.a.b:undefined)?api.a.b.c:undefined)) 
> {try later}
>
> but can't be written with ?:
>
> The best in that case would be to be able to do : if (!api.a.b.c) {try 
> later}
>
> Why in accessors the attempt to access a property of |undefined| could 
> not return |undefined| itself ?
>
>
> Le 13/06/2012 09:45, T.J. Crowder a écrit :
>> On 13 June 2012 06:52, Brendan Eich <brendan at mozilla.org 
>> <mailto:brendan at mozilla.org>> wrote:
>>
>>     People don't default on the caller side (at the callsite) much,
>>     in my experience. Dave may be seeing other sources, but it's
>>     extremely rare in my experience to see
>>
>>
>> I'm with Dave on this, I do it fairly regularly, usually when a 
>> function turns around and calls another one with the arg and has no 
>> other use for the arg:
>>
>> function doSomethingNifty(a, b) {
>>     return doSomethingVerbose({
>>         x: 1,
>>         y: a,
>>         z: b ?: 5
>>         // ...
>>     });
>> }
>>
>> ?= looks great, and Wes' point about confusion re ||= (or even |||=) 
>> and boolean logical operators definitely kills my preferred ||| for 
>> the non-assignment form if there's going to be an assignment form -- 
>> and we all want an assignment form.
>>
>> Is the reason for using ?: rather than ?? because we may want it for 
>> my desired second ternary? E.g., from my other message:
>>
>> a = b ?? c : d;
>>
>> meaning
>>
>> a = b !== undefined ? c : d;
>>
>> Or that we want it (now, or in reserve) for something else? Because 
>> if not, I'd prefer to see ?? rather than ?:. It's easier to type and 
>> the double ?? calls back to the related ||. But again, only if we 
>> don't want ?? (now, or in reserve) for something else.
>>
>> Very much looking forward to ?: (however we spell it) and ?=.
>>
>> -- T.J.
>>
>>
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>
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