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Date: Mon, 28 Jul 2014 23:49:57 +0800
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To: Andrea Faulds <ajf@ajf.me>
Cc: Derick Rethans <derick@php.net>, Nikita Popov <nikita.ppv@gmail.com>, Julien Pauli <jpauli@php.net>, 
	PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Thoughts on C version supported for PHP-Next
From: laruence@gmail.com (Xinchen Hui)

=E5=8F=91=E8=87=AA=E6=88=91=E7=9A=84 iPad

> =E5=9C=A8 2014=E5=B9=B47=E6=9C=8828=E6=97=A5=EF=BC=8C22:20=EF=BC=8CAndrea=
 Faulds <ajf@ajf.me> =E5=86=99=E9=81=93=EF=BC=9A
>
>
> On 28 Jul 2014, at 15:00, Derick Rethans <derick@php.net> wrote:
>
>>> Well, we don=E2=80=99t need to allow all of C99. We can simply allow us=
ing
>>> features that are widely supported and actually useful. For example,
>>> declarations between statements,
>>
>> I think that makes code a lot less readable, so I would not be in favour
>> allowing this in our coding guidelines.
>
> Really? I=E2=80=99ve found that declaring everything in advance makes for=
 hard-to-read code. To take an example from code I=E2=80=99ve written (admi=
ttedly not C code - GML if anyone=E2=80=99s curious - but it might as well =
be), the first line of a function looked like this:
>
>    var list, hashList, text, i, pluginname, pluginhash, realhash, url, ha=
ndle, filesize, progress, tempfile, tempdir, failed, lastContact, isCached,=
 env;
>
> Even broken onto multiple lines, declaring everything at once isn=E2=80=
=99t nice. For large functions (and some functions have to be large necessa=
rily), declaring everything at the start just means a long list of variable=
s and I would argue impairs code readability.
>
> You should declare variables when and where you need them. If everything =
is done at the top, you have to scroll up to check the type of a variable. =
It also means that now-unused variables are less obvious as the declaration=
s are far away from the usage, so you probably won=E2=80=99t spot that it=
=E2=80=99s useless unless you look at your compiler warnings.
>
> Actually, a similar issue popped up in the code where that example was fr=
om. The language it was written in had some unfortunate properties, one of =
which was that variables not explicitly declared would instead be treated a=
s properties of the current object. Because all the variables were declared=
 at the start of the function, it was easy to miss the fact that some varia=
bles being used had not actually been declared. Of course this specific iss=
ue doesn=E2=80=99t exist in C, but it is an example of why having to declar=
e all your variables at the start of a function isn=E2=80=99t really a good=
 thing.
>
> If nothing else, I think we should use C99=E2=80=99s ability to declare v=
ariables between statements. It makes it more likely mistakes will be spott=
ed, eases reading code, and as far as I am aware, is widely supported.
I really hate this.
Thanks
>
> --
> Andrea Faulds
> http://ajf.me/
>
>
>
>
>
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