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Subject: Re: [PHP-DEV] PATCH: anonymous functions in PHP
From: sean@caedmon.net (Sean Coates)

> If it would create anonymous function compile-time, it would be a big
> advantage to Wez's patch because then this function could be cached.
> Thinking about this, maybe it is the reason enough to do this even if
> it's not real closure.

On mulling this over a bit more, other than quick one-off callbacks
(which would definitely benefit from avoiding compile on every request),
one of the key reasons to use create_function() is actually to create
dynamic functions:

$fancyVer = create_function('', 'return "PHP " . phpversion();');
// could be optimized as:
$fancyVer = create_function('', 'return "PHP ' . phpversion() .'";');

(the latter only calls phpversion() at declaration, not each time the
lambda runs)

Since phpversion() is available globally, this isn't a problem. But what
happens if we want to use a variable, instead?

$ver = phpversion();
$fancyVer = create_function('', "return 'PHP $ver';");
// this currently works ^

How would this be rewritten, though?
$ver = phpversion();
$fancyVer = function () { return "PHP $ver"; };

where would $ver come from? the parent scope? the lambda's local scope?
what if it's defined in both places?

S