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Date: Wed, 18 Apr 2012 07:31:39 +0900
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To: Stefan Neufeind <neufeind@php.net>
Cc: php-dev <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Variable-length args by reference
From: yohgaki@ohgaki.net (Yasuo Ohgaki)

Hi,

2012/4/18 Stefan Neufeind <neufeind@php.net>:
> On 04/18/2012 12:02 AM, Stefan Neufeind wrote:
>> Hi,
>>
>> the topic of variable argument-lists for functions in connection with
>> getting the parameters by reference came up. This is currently not
>> possible with func_get_args(), though a "hack" with debug_backtrace() is
>> possible.
>>
>> How would you think about extending func_get_args() and func_get_arg()
>> to allow for:
>>
>> =A0 =A0 =A0 $args =3D func_get_args(FUNC_GET_ARGS_BY_REFERENCE);
>> =A0 =A0 =A0 $arg0 =3D func_get_arg (0, FUNC_GET_ARGS_BY_REFERENCE);
>>
>> (default would be FUNC_GET_ARGS_BY_COPY)
>>
>>
>> Currently only the following "hack" works:
>>
>> function calc()
>> {
>> =A0 =A0 =A0 $d =3D debug_backtrace();
>> =A0 =A0 =A0 =A0 $args =3D $d[0]['args'];
>> =A0 =A0 =A0 =A0 $args[0] *=3D 2;
>> =A0 =A0 =A0 =A0 $args[1] *=3D 2;
>> }
>>
>> $a =3D 5;
>> $b =3D 7;
>> var_dump ($a, $b);
>> calc(&$a, &$b);
>> var_dump ($a, $b);
>
> Hmm, that example also only works because of the call-time
> pass-by-reference? *sigh*
> Sorry, I forgot those ampersands in the call to calc(). Doesn't work
> without.
>
> I hope the idea is clear though. Any chance we might make this possible
> through func_get_args()?

I don't know what you would like to do, but

function calc(&$args =3D NULL) {
    var_dump(count($args)); // num of args
    $args[1] *=3D 2;
}
calc(array(1,2,3,4));

would work.

Regards,

--
Yasuo Ohgaki