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Message-ID: <4DA2F1FC.1020805@yahoo.com.au>
Date: Mon, 11 Apr 2011 22:20:12 +1000
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To: Hannes Landeholm <landeholm@gmail.com>
CC: Stas Malyshev <smalyshev@sugarcrm.com>, internals@lists.php.net
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Subject: Re: [PHP-DEV] proposed access modifier "silent" ... was: Re: [PHP-DEV]
 Implicit isset/isempty check on short-ternary operator
From: mail_ben_schmidt@yahoo.com.au (Ben Schmidt)

I think another problem with using @ is that it is done by the caller,
not the callee, so it doesn't allow functions like issetor() to be
implemented in userland without expecting every caller to do pass the
variable while silencing errors.

I also don't think the inconvenience is restricted to arrays. I
frequently use the idiom isset(X)?X:Y with X simply being a variable.
It's not just about silencing a notice, but about providing an
alternative/default value.

If doing the suppression of undefined notices be better if the ? was put after the 
opening square bracket, thereby removing the ambiguity (which I think would be 
more troublesome than you think)? $array[?"foo"]

Ben.



On 11/04/11 6:10 PM, Hannes Landeholm wrote:
> @ is not convenient since it turns off error reporting for all errors. I
> don't know how many times I've silenced a notice and got a blank page in my
> face as a "thank you for accidentally silencing that fatal error too".
>
> "Silent" is reserved for the purpose of the silence operator though @ so
> using that as a keyword for something else would be confusing.
>
>
> It just struck me that the ~real~ problem is that sometimes you want array
> access that should define undefined indexes as being null (a good
> placeholder for this purpose). How about (instead of the previously proposed
> ?? and isnotempty and whatnot) simply changing the "array access syntax" to
> simply allow an optional "?" operator at the end signaling that the
> condition where the index isn't defined isn't unexpected?
>
> For example:
>
> $value = isset($arr["foo"])? $arr["foo"]: null;
> $value = isset($arr[$foo])? $arr[$foo]: null;
>
> would be replaced with: (respectively)
>
> $value = $arr["foo"?];
> $value = $arr[$foo?];
>
> it would also worked chained:
>
> $value = $arr["foo"?]["bar"]["baz"?]
>
> (if [foo] doesn't exist value will be null.. if [foo] exists [foo][bar] is
> expected to exist but [foo][bar][baz] may or may not exist... if not, value
> will once again be null)
>
> This way it would only apply to array access which was a +1 for some.
>
> This could also be extended too replace null with something different (by
> allowing an expression after the "?" like "null" or "foo" . "bar") but I
> think careful use-case research should be done to determine if it's really
> needed first...
>
> I realize this partially collides with the use of ? so it would be more
> difficult to implement but it's far from impossible.. it just requires a
> little ahead-parsing in brackets [] to know if the "?" is a ternary if or if
> it's a "not exists is not undefined" operator (is the : missing or not?).
> Otherwise "??" could simply be used instead or a completely different
> operator...
>
> ~Hannes
>
> On 11 April 2011 04:47, Stas Malyshev<smalyshev@sugarcrm.com>  wrote:
>
>> Hi!
>>
>>   @.
>>>
>>
>> Note however it does not exactly "turn off" the warning, only changes it to
>> not reported. It's still generated and can be picked up by handlers, for
>> example.
>> --
>> Stanislav Malyshev, Software Architect
>> SugarCRM: http://www.sugarcrm.com/
>> (408)454-6900 ext. 227
>>
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
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>>
>>
>