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Date: Sun, 21 Sep 2008 00:43:41 +0100
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References: <48D47532.8080102@chiaraquartet.net>
	 <e666c3890809200924t28f1c585kad77729dd608c5ad@mail.gmail.com>
Subject: Re: [PHP-DEV] solving the namespace conflict issues between function/static method class constant/ns constant
From: rquadling@googlemail.com ("Richard Quadling")

2008/9/20 Etienne Kneuss <colder@php.net>:
> Hello,
>
> On Sat, Sep 20, 2008 at 5:59 AM, Greg Beaver <greg@chiaraquartet.net> wrote:
>> Hi all,
>>
>> There is a problem in the namespace implementation.  This code demonstrates
>> the issue:
>>
>> code.inc:
>> <?php
>> namespace foo;
>> class test {
>> const my = 1;
>> static function bar(){}
>> }
>>
>> namespace foo::test;
>> const my = 2;
>> function bar(){}
>> ?>
>>
>> main.php:
>> <?php
>> include 'code.inc';
>> foo::test::bar(); // always calls namespace function
>> call_user_func(array('foo::test', 'bar')); // the only way to call static
>> method
>> echo foo::test::my; // always 2
>> $a = new foo::test;
>> echo $a::my; // the only way to access foo::test::my
>> ?>
>>
>> There are 5 ways to solve this:
>>
>> 1) document it and hope no one uses it [this is the current strategy, minus
>> the documentation part]
>> 2) add a fatal error on conflicting names.
>>
>> http://pear.php.net/~greg/ns_method.func.conflict.patch.txt
>>
>> Unfortunately, this can only work for methods/functions, as namespace
>> constants are actually defined at run-time, and so conflicts can't be
>> detected until then, which does not provide any benefit (you want to catch
>> this conflict at compile-time).
>>
>> 3) create a disambiguation method.
>>
>> http://pear.php.net/~greg/ns.func_const.patch.txt
>>
>> This introduces function:: and const:: as prefixes to disambiguate.
>>
>> <?php
>> function::foo::test::bar(); // always calls namespace function
>> foo::test::bar(); // always calls static method if defined, falls back to ns
>> function if not
>> const::foo::test::my; // namespace constant
>> foo::test::my; // class constant
>> ?>
>>
>> The drawback of this approach is that "foo::test::bar" will always look for
>> class "foo::test", which means if autoload is defined, it will be called for
>> all non-prefixed function calls.  Unfortunately, the only other keyword for
>> disambiguating would be "class::" as in "class::foo::test::bar()" but this
>> is excessively confusing.
>>
>> 4) remove functions/constants from namespaces
>> 5) a simply syntax change to namespaces, introducing a new concept:
>> namespace element.
>>
>> A namespace element is a class, function or constant defined within a
>> namespace declaration:
>>
>> <?php
>> namespace foo;
>> class bar {} // class element bar in namespace foo
>> function bar(){} // function element bar in namespace foo
>> const bar=1; // const element bar in namespace foo
>> ?>
>>
>> This is similar to class elements:
>>
>> <?php
>> class foo {
>> function bar(){} // method element bar in class foo
>> const bar=1; // constant element bar in class foo
>> public $bar=1; // variable element bar in class foo
>> }
>> ?>
>>
>> Currently, this code:
>>
>> <?php
>> namespace foo::bar;
>> class buh{}
>> ?>
>>
>> creates a class named "foo::bar::buh", essentially joining the namespace
>> "foo::bar" and its class element "buh" with the separator "::".  This turns
>> out to be the root of the problem with the conflicts between class elements
>> and namespace elements.  The last patch introduces a new namespace element
>> operator to delineate the boundary between namespace name and element name.
>>  For the patch, I recycled T_OBJECT_OPERATOR (->).
>>
>> current way:
>> <?php
>> foo::bar->test(); // namespace foo::bar, call to function element test()
>> foo->bar::test(); // namespace foo, call to static method element test() in
>> class element bar
>> foo->myconst; // namespace foo constant myconst
>> foo::myconst; // class foo constant myconst
>> ?>
>>
>> The patch is at:
>>
>> http://pear.php.net/~greg/ns.element.patch.txt
>>
>> This is the most extensive change.  The patch preserves :: as global element
>> accessor (::strlen() calls strlen internal function, for instance).  I'm
>> happy to answer any other questions.
>>
>> So, these are the choices.  I suggest we all take a rational look at the
>> options, and understand the consequences of each, and make the best choice
>> possible.
>>
>> Thanks,
>> Greg
>
> Good work, but I (and I'm probably not alone) can't really keep up
> with all those namespace threads and proposals for changes and
> resolution fixes and this and that,so :
>
> Please use our nice RFC system!
>
> Regards
>
> --
> Etienne Kneuss
> http://www.colder.ch
>
> Men never do evil so completely and cheerfully as
> when they do it from a religious conviction.
> -- Pascal
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>

How feasible would it be to use # as the namespace separator. I know #
is used for comments, but with /* */ and // that all seems covered.

namespace#function() vs class::static()

Seems like a winner. Just a whole ton of BC though for those using #
for comments.

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!"