Hello,
On Mon, Nov 16, 2009 at 2:51 PM, Mathieu Suen <mathieu.s...@easyflirt.com>wrote:
> 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; }
>
>
You simply cannot take $a = ..; as a variable declaration, otherwise $a = 2;
if (..) { $a = 3; } echo $a; would output 2, which is wrong.
In fact, you haven't really solved any of the two problems I described.
> 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...
>
>
It's not strange, PHP does not have specific scopes for control structures,
and $_GET/$_POST can be considered as global variables. Of course it may not
be like language X or Y, but it makes sense considering the paradigm behind
variables in PHP.
>
> 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
>
>
--
Etienne Kneuss
http://www.colder.ch
