Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:40589
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain chiaraquartet.net from 208.83.222.18 cause and error)
Message-ID: <48D5C151.1070607@chiaraquartet.net>
Date: Sat, 20 Sep 2008 22:36:49 -0500
User-Agent: Thunderbird 2.0.0.16 (X11/20080724)
MIME-Version: 1.0
To: Larry Garfield <larry@garfieldtech.com>
CC: internals@lists.php.net
References: <48D47532.8080102@chiaraquartet.net> <e666c3890809200924t28f1c585kad77729dd608c5ad@mail.gmail.com> <10845a340809201643q59e27211i471e09241f7253b1@mail.gmail.com> <200809202000.38870.larry@garfieldtech.com>
In-Reply-To: <200809202000.38870.larry@garfieldtech.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] solving the namespace conflict issues between function/static
 method class constant/ns constant
From: greg@chiaraquartet.net (Gregory Beaver)

Larry Garfield wrote:
> On Saturday 20 September 2008 6:43:41 pm Richard Quadling wrote:
> 
>>>> 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.

[snip]

> I agree that #5 seems like the best solution.  The problem is caused by the 
> double meaning of ::.  All of the other solutions feel like bandaids.  
> 
> Of course, the problem then is finding a symbol that is not already used.  I 
> don't think reusing -> is any wiser than reusing ::.  # would be great if it 

Let's be clear.  Here is a sample of code with the new syntax:

<?php
namespace name::still::has::double::colon;
const oscopy = 1;
class blow{
const byblow = 1;
static function hard(){}
}

namespace another::name;
use name::still::has::double::colon;

// fully qualified name:
// note that -> is only used once
// to specify the boundary between namespace name and namespace member.
$a = new name::still::has::double::colon->blow;
$a = new colon->blow;
// static method call
colon->blow::hard();
// or
name::still::has::double::colon->blow::hard();

// ns constant
echo colon->oscopy;

namespace blow;
function hard(){}

namespace a::third::name;
// demonstrate importing a class name
// which is different from importing a namespace name
use name::still::has::double::colon->blow;

// class static method
blow::hard();
// namespace function
::blow->hard();
// class constant
echo blow::byblow;
?>

Two important things to note:
 - ambiguity between namespace name and class name is eliminated
<?php
namespace foo;
class test{
}
namespace foo::test;
class test{}
namespace third;
use foo::test;
$a = new test;  // this is namespace foo, class test
$a = new test::test; // this is namespace foo::test, class test
?>
 - this separator is self-documenting.  One does not need to grep source
code to determine whether blah->thing is a namespaced function or a
static method of class blah.  The same is true of use statements.  It is
crystal clear whether we are importing a namespace or a class name.
This will make debugging someone else's code a lot easier than it
otherwise would be.

Jochem has informed me he is taking care of the wiki RFC for this stuff.
 I am allergic to wikis, unfortunately.

Thanks,
Greg