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Date: Sat, 8 Mar 2014 23:33:18 +0000
Cc: Marco Schuster <marco+php@m-s-d.eu>,
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To: Chris Wright <daverandom@php.net>
Subject: Re: [PHP-DEV] Idea: ifdef-like feature to ease userland BC
From: ajf@ajf.me (Andrea Faulds)

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On 8 Mar 2014, at 23:01, Chris Wright <daverandom@php.net> wrote:

> Imagine that some_func() is only ever used in the context of a
> foreach. For BC reasons, we have to keep this API. Since 5.5, we could
> use a generator (yes, we could use an iterator, I said it was
> contrived :-P), but we need to provide BC with older PHP versions:
>=20
> function some_func() {
>    $fp =3D fopen('some_file.ext');
> #if PHP_VERSION >=3D 5.5.0
>    while (false !=3D=3D $line =3D fgets($fp)) {
>        yield $line;
>    }
> #else
>    $result =3D array();
>    while (false !=3D=3D $line =3D fgets($fp)) {
>        $result[] =3D $line;
>    }
>    return $result;
> #endif
> }

Ah, that=92s a good example.

> **However** the thought occurs that, while potentially useful, a
> pre-processor of this nature could easily be done with a userland
> implementation, a composer dependency and a composer
> after-install/after-update script=85

Right. You could also just use include or require to load a file with a =
PHP 5.6 implementation or a PHP 5.5 implementation, conditionally, =
though for differences which are just a few lines, this would be =
inconvenient.
--
Andrea Faulds
http://ajf.me/





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