Description:
------------
This is really a request to make an exception to the following limitation:

"The default value must be a constant expression, not (for example) a variable, a class member or a function call."

Quoted from: http://nl2.php.net/manual/en/functions.arguments.php

It's my guess that this has to do with the vars scope getting messy, but I think superglobals would qualify for an exception to this.

Constants are already accepted.

Reproduce code:
---------------
function foo($bar=$_SERVER['REMOTE_ADDR'])
{
  echo('Given IP is: '.$bar.'<br />');
}
foo('192.168.1.1');
foo();

Expected result:
----------------
I would expect PHP to echo the submitted string the first function-call. And echo the clients IP the second call.

Actual result:
--------------
I get the following parse error, which is correct, but not desirable I think.

Parse error: parse error, unexpected T_VARIABLE in path\to\file.php on line 1