This is a "testing of the waters" RFC. If there is interest, it will be
followed with a patch. It should be noted that the patch for this has
been available through the various vortexes of namespace syntax for over
a year now, and it is an extremely simple patch.
[RFC]
Implement importing of functions to complement importing of classes and
namespaces.
example:
<?php
namespace foo;
include 'blah.php'; // defines function bar in namespace oof
use function oof\bar;
use function \strlen;
bar(); // calls oof\bar()
$a = strlen('hi'); // calls global function strlen
?>
[Problems this solves/Use cases]
(1) Readability:
* can make code more readable, much like importing classes/namespaces,
by shortening line lengths and simplifying complex compound expressions
(2) Backwards/Forwards compatibility
* Occasionally, an internal function is extended with additional
parameters. With function import, this can be accomplished in old versions.
Example (pretend parameter "encoding" is added to strlen() in PHP 6.0):
<?php
namespace Util {
function strlen($string, $encoding = 'ISO-8559-1')
{
$a = phpversion();
if ($a[0] >= 6) {
return \strlen($string, $encoding); // use internal implementation
}
// now for the simulated parameter
switch ($encoding) {
...
}
}
}
use function Util\strlen;
// now code following will work in all PHP versions, and is
forward-compatible to PHP 6
?>
[Proposed syntax changes]
Function import is accomplished with the keyword "function" (T_FUNCTION
token) as in
T_USE T_FUNCTION [use_statement]
use_statement can be any of \func or nsname\func or \nsname\func
Samples:
<?php
use function \globalfunc;
use function nsname\func;
use function \nsname\func;
?>
Just like the regular implementation of use for classes/namespaces:
<?php
use function globalfunc;
?>
will raise a warning that this has no effect (import in global scope of
unqualified name is meaningless).
<?php
namespace inside\namespace;
use function globalfunc;
?>
will act like:
<?php
namespace inside\namespace;
use function \globalfunc;
?>
[Drawbacks]
1) requires changing the engine near beta
2) adds new syntax to namespaces
[Non-issues/Slight issues]
1) would introduce one hash lookup on unqualified function calls at
compile-time if any "use" statement exists in the script, which is
unlikely to be detectable as a performance difference for even the
largest scripts.
Thanks,
Greg
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