Operators ||= and &&=
brendan at mozilla.com
Wed May 6 16:33:44 PDT 2009
On May 6, 2009, at 3:13 PM, Neil Mix wrote:
> On May 6, 2009, at 4:53 PM, Ash Berlin wrote:
>>>> You could make a case for adding a ?? operator for symmetry.
>>>> Example of usage:
>>>> some_func(a, b ?? "c" );
>>> Roger that, given ??= it would be strange to leave out ??.
>>> I'm still trying to leave out both ;-).
>> I'm quite partial to an undefined-or operator :)
> Wouldn't it make more sense to have ||| and &&& operators? We're
> really just discussing a different form of boolean logic here, why
> not go-the-distance and draw parallels to ===. (I think I'm proving
> Brendan's point :P)
Which point? ;-)
I tried like hell in 1996-7 to get == and != to be what became ===
and !==, in JS1.2, at the same time ES1 was being standardized. At
that point Microsoft had less market share than Netscape and therefore
did not want to risk "breaking the web", so we standardized == and !=
as the crap-tastic non-equivalence relations they are, and added ===
(Adding better forms and hoping to deprecate their precursors is a
constant theme on the Web; nothing against Microsoft's position here,
from this remove in time.)
With the current topic, IMHO there's nothing wrong with || to "fix".
The boolish (truthy/falsy) tolerance and value-preserving, short-
circuiting evaluation model are good things in general. So a different
form for a different operator should be used. And C# is our cousin in
Ecma, ECMA-334, which if it has been maintained, has ?? (if not ??=)
in it by now.
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