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Subject: namespace improvements to be committed very soon - final review
From: greg@chiaraquartet.net (Gregory Beaver)

Hi,

I've been furiously working behind the scenes with Stas and Dmitry, and
have some enhancements to namespaces in the form of 2 patches.

1) multiple namespaces per file
2) use ::name;

1) multiple namespaces per file

This is implemented as such:

<?php
namespace one;
use Blah::A;
// code
namespace two;
use Foo::A;
?>

The example above shows that imported names are reset at each namespace
declaration.  There is no prohibition on this code:

<?php
namespace one; {
use Blah::A;
// code
}
namespace two; {
use Foo::A;
// code
}
?>

Users who wish to use brackets may do so.  The performance penalty
imposed by using brackets is minor for some cases, and for users who are
following the recommended practice of 1 namespace per file, the syntax
is ideal.

Patch is:

http://pear.php.net/~greg/namespace/PHP_5_3/multi.patch.txt
http://pear.php.net/~greg/namespace/PHP_6_0/multi.patch.txt

Note that non-namespaced code cannot be present in a file containing
namespaces.  For users who are bundling, this will mean you will need to
create 2 files, one with non-namespaced code, and one with namespaced
code.  This minor prohibition is a design decision, not a technical
problem in the implementation.

2) use ::name

This code:

<?php
namespace Whatever;
use MDB2; // import PEAR's ::MDB2 from global scope
$a = MDB2::connect();
?>

is currently impossible, which will make namespacing old code harder. 
The patch introduces this new syntax to import names from the global
namespace:

<?php
use ::MDB2, ::strlen as len;
?>

http://pear.php.net/~greg/namespace/PHP_5_3/use.patch.txt
http://pear.php.net/~greg/namespace/PHP_6_0/use.patch.txt

These patches are for review of both serious technical and serious
implementation issues.  In order to help move things along, I'd like to
define "serious" as something directly related to the implementation
that would cause a failure in PHP's ability to run scripts
deterministically, or some kind of memory leak/crash.

commit is planned for the next 24 hours or so, but of course any issues
found in review can be fixed.  The patches are short, so in the worst
case, reverting is not difficult.

Thanks,
Greg