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Date: Wed, 26 Aug 2015 18:07:10 +0100
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To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] PHP 7.1 - Address PHPSadness #28?
From: craig@craigfrancis.co.uk (Craig Francis)


On 26 Aug 2015, at 16:06, Rowan Collins <rowan.collins@gmail.com> wrote:

> Craig Francis wrote on 26/08/2015 14:53:
>> On 26 Aug 2015, at 12:36, Rowan Collins <rowan.collins@gmail.com> =
wrote:
>>=20
>>> Fortunately, the function you are looking for already exists: =
http://php.net/array_key_exists
>> It does, although I seem to have edited that out of my reply... was =
trying to keep it short ;-)
>=20
> You could have kept the reply even shorter by omitting examples for =
which the language already provides the solution ;)


I provide examples to help explain that I (and I suspect most =
developers) default to using isset which works on either.

Just because there is a function, which does not exactly roll off the =
tongue (plus the fun of the needle/haystack ordering issue), does not =
mean it gets used (even if it is the correct thing to use).




>> At the moment I'm out of examples (bit busy at the moment), but I do =
know that when I'm doing an isset() check, I'm really wanting to know if =
the variable (or key) exists
>=20
> Stop. As soon as you say "or key" you completely defeat your argument. =
The whole thing is ONLY worth discussing if you can come up with an =
example of an actual variable having unknown existence.


I say "or key" because developers use the isset function on both $var =
and $var['key']... yes, I know they are different, but when you are =
coding in PHP an isset check is an isset check (well it isn't, because =
the variable may technically exist).

If this is a problem, maybe PHP should raise a notice when isset is used =
on arrays?




>> where NULL may be a perfectly valid value.
>=20
> It's not that NULL isn't a valid value; it's that "doesn't exist" =
isn't a meaningful state for a variable. It's like checking if the =
current line number is greater than 100, it shouldn't mean anything to =
the compiled program. See the SO answer I linked earlier for more =
thought experiments along these lines.


I think you have been spending too much time in C.

Most of the PHP code bases I've worked on set variables to NULL at some =
point (and they are not calling unset, because that isn't the =
intention).