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Message-ID: <10845a340807220737v47c7ed5dm37d272007ff33521@mail.gmail.com>
Date: Tue, 22 Jul 2008 15:37:47 +0100
Reply-To: RQuadling@GoogleMail.com
To: "Rodrigo Saboya" <rodrigo.saboya@bolsademulher.com>
Cc: internals@lists.php.net
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Subject: [PHP-DEV] Modify language grammar to allow commas to skip defaulted parameters.
From: rquadling@googlemail.com ("Richard Quadling")

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2008/7/22 Richard Quadling <rquadling@googlemail.com>

>
>
> 2008/7/22 Rodrigo Saboya <rodrigo.saboya@bolsademulher.com>
>
> Evan Priestley escreveu:
>>
>>> This was floated in 2003 but had weak advocation and didn't seem to come
>>> to a decisive resolution:
>>>
>>>    http://marc.info/?l=php-internals&m=106685833011253&w=2
>>>
>>> Basically, the proposal is to modify the grammar to allow trailing commas
>>> in function and method calls, so this becomes a parseable PHP construct:
>>>
>>>    f(1, 2, 3,);
>>>
>>> This patch applies only to function and method calls; it does not apply
>>> to function or method definitions. It also does not allow the degenerative
>>> case of "f(,)".
>>>
>>> The real value of relaxing this rule is in nontrivial cases that span
>>> across multiple lines:
>>>        sprintf(
>>>        'long example pattern with %d conversions: %s',
>>>        $several,
>>>        $conversions
>>>    );
>>>
>>>
>> You could just do this:
>>
>> sprintf(
>>    'long example pattern with %d conversions: %s'
>>    ,$several
>>    ,$conversions
>> );
>>
>> I really don't see a great benefit here, and as you pointed out it would
>> make code written with trailing commas incompatible with previous versions
>> of PHP.
>>
>> --
>> Rodrigo Saboya
>>
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>>
> Just thinking of other languages that allow you to skip params simply by
> using commas. Whilst this isn't supported in PHP, allowing a trailing comma
> and skipped parameters could look quite interesting!
>
> foo(,,,,,,,);
>
>
> I must admit, I get stung with this in JS when I'm building AJAX option
> sets through Prototype for IE (I think like arrays in PHP which allow
> trailing ,), but I soon learned to do it properly.
>
> I don't see this as a huge advantage.
>
> Regards,
>
> Richard Quadling.
> --
> -----
> Richard Quadling
> Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731
> "Standing on the shoulders of some very clever giants!"
>

Actually, would allowing PHP to skip defaulted parameters be a better
facility to add?

function foo($opt1 = Null, $opt2 = Null){}

foo(,True);

Hmm. Doesn't look good does it. But, useful. Having to supply the default
value if you don't want to override the default is sort of
counter-intuitive. Suppling nothing should equal the default value.

Regards,

Richard.


-- 
-----
Richard Quadling
Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731
"Standing on the shoulders of some very clever giants!"

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