2009/11/16 Mathieu Suen <mathieu.s...@easyflirt.com>:
> Maybe you find it useless. That is just a discussion. I don't expect PHP to
> change thought it should IMHO, especially now that you are introducing
> closure. :)
>
> For those who complain about the foreach behavior (including me) that's
> typically a scope issue. Doing an automatic unset isn't the right way of
> solving it.
> Somehow this foreach exemple show why you don't want dynamic scoping.
>
> Victor Bolshov a écrit :
>>
>> That's a completely useless discussion, isn't it? Whoever is "right"
>> with his opinion regarding scoping - nobody will (and nobody would
>> like to) change PHP's scoping for those reasons as it would break too
>> much existing code.
>>
>> 2009/11/16 Mathieu Suen <mathieu.s...@easyflirt.com>:
>>>
>>> Etienne Kneuss a écrit :
>>>>
>>>> Hello,
>>>>
>>>> On Mon, Nov 16, 2009 at 2:10 PM, Mathieu Suen
>>>> <mathieu.s...@easyflirt.com>wrote:
>>>>
>>>>> Pierre Joye a écrit :
>>>>>
>>>>> On Mon, Nov 16, 2009 at 12:07 PM, Mathieu Suen
>>>>>>
>>>>>> <mathieu.s...@easyflirt.com> wrote:
>>>>>>
>>>>>> • Pensez à l'environnement, n'imprimez cet e-mail qu'en cas de réelle
>>>>>>>
>>>>>>> nécessité
>>>>>>>
>>>>>> Discussing endlessly an issue only because you do not understand it is
>>>>>> also an environmental problem, please consider to read the manual and
>>>>>> stop to use every single channel to ask the same questions again and
>>>>>> again.
>>>>>>
>>>>>> Salutations,
>>>>>>
>>>>> That's not a question, look at what lisp dose and scheme.
>>>>> Look at the lambda calculus etc.
>>>>>
>>>>> The variable inside the foreach should not be captured outside.
>>>>> Like function argument. And again and again you are doing the same
>>>>> mistake:
>>>>>
>>>> Static scoping is closely related to variable declaration. In PHP, there
>>>> is
>>>> no such thing as a variable declaration statement (apart from function
>>>> arguments or class members, which are correcly scoped).
>>>
>>> I am pretty sure you can have static scoping without declaration
>>> statement.
>>> Or you can consider "$a = 2" as a declaration statement.
>>> Which imply that
>>>
>>> if (..) { $a = 2; } else { $a = 3; }
>>>
>>> Produce 2 bindings of $a or can be a free if you 'declare' it outside .
>>> As:
>>>
>>> $a = null;
>>> if (..) { $a = 2; } else { $a = 3; }
>>>
>>> What's strange is that part of the language is statically scoped will the
>>> other part is dynamic.
>>> See function vs. if, loop statement.
>>>
>>> Even worst if you think of the $_GET variable which should have a special
>>> scope...
>>>
>>> There is only an
>>>>
>>>> assign statement, that may introduce a new variable, or not. Without
>>>> such
>>>> a
>>>> declaration statement, static scoping doesn't make much sense.
>>>>
>>>> For example:
>>>>
>>>> if (..) { $a = 2; } else { $a = 3; }
>>>>
>>>> echo $a;
>>>>
>>>> would either fail or require some branch analysis at compile time to
>>>> work.
>>>> which we can't really afford.
>>>>
>>>> Or:
>>>>
>>>> $a = 2;
>>>>
>>>> if (...) { $a = 3; }
>>>>
>>>> There is no way of stating whether $a = 3; should be for a $a that is
>>>> unrelated to the outer $a.
>>>>
>>>>
>>>> In other words, the kind of scoping you want will most likely never be
>>>> implemented in PHP.
>>>>
>>>> Best
>>>>
>>>>
>>>>> "Dynamic scoping is primarily interesting as a historical mistake: it
>>>>> was
>>>>> in the earliest versions of Lisp,
>>>>> and persisted for well over a decade. Scheme was created as an
>>>>> experimental
>>>>> language in part to experiment
>>>>> with static scope. This was such a good idea that eventually, even
>>>>> Common
>>>>> Lisp adopted static scope.
>>>>> Most modern languages are statically scoped, but sometimes they make
>>>>> the
>>>>> mistake of recapitulating this
>>>>> phylogeny. So-called “scripting” languages, in particular, often make
>>>>> the
>>>>> mistake of implementing dynamic
>>>>> scope (or the lesser mistake of just failing to create closures), and
>>>>> must
>>>>> go through multiple iterations before
>>>>> they eventually implement static scope correctly."
>>>>> - Shriram Krishnamurthi, "Programming Languages:
>>>>> Application and Interpretation" section 6.5:
>>>>>
>>>>> -- Mathieu Suen
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> PHP Internals - PHP Runtime Development Mailing List
>>>>> To unsubscribe, visit: http://www.php.net/unsub.php
>>>>>
>>>>>
>>>>
>>>
>>> -- Mathieu Suen
>>>
>>> --
>>> PHP Internals - PHP Runtime Development Mailing List
>>> To unsubscribe, visit: http://www.php.net/unsub.php
>>>
>>>
>>
>
>
> -- Mathieu Suen
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
Would an E_WARNING, or E_STRICT (maybe), be suitable here?
<?php
$array = array(1 => 'one', 2 => 'two', 3 => 'three');
foreach($array as $index => &$value) {
echo "$index is $value\n";
}
// MAYBE this like could generate an E_WARNING: variable $s previously
used as a reference in file:... line:5
$value = 'Troi';
print_r($array);
?>
Whilst the documentation is quite clear, I suspect a bit of
hand-holding (in the form of an error of some type) could be
appropriate.
But even by my own standards (whatever they may be!) I think that
looks dubious. Assigning a value to a reference supplied as a
parameter to a function wouldn't be considered an error.
So, extend this error to only be for foreach()'s ...
Again, yuck, too specific (though mktime() warranted an error when
there is _seemingly_ nothing wrong with it).
Richard.
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