Dynamic "use" to PHP anonymous function

Question

In PHP there is a function called extract, which takes an array, and transforms your data into PHP variables. This function is very useful when I need to send variables to an include. Ex.

    extract(array( "test" => 123 ));
    require "test.php"

So test.php: print($test); Returns: 123

I need to do the same with functions (which I may not know). PHP 5.4 has support for use (Anonymous Function), which is quite interesting. Ex.

$test = 123;
call_user_func(function() use($test) {
    print($test);
});

However, I need to pass variables with other names and amounts. Something like:

$useArgs = array( "a" => 1, "b" => 2, "c" => 3 );
call_user_func(function() use(extract($useArgs)) {
    print($a);
    print($b);
    print($c);

    if(isset($d)) {
        print($d);
    }
});

How is this possible?

kba · Accepted Answer · 2013-07-15 01:11:38Z

2

Just call extract() from inside your function

$useArgs = array( "a" => 1, "b" => 2, "c" => 3 );
call_user_func(function() use($useArgs) {
    extract($useArgs);
    print($a);
    print($b);
    print($c);

    if(isset($d)) {
        print($d);
    }
});

answered Jul 15, 2013 at 1:11

kba

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3 Comments

Cole Tobin Over a year ago

Don't you still need to declare $useArgs as global?

kba Over a year ago

No, why would you need that? Why would you use use if you also had to use global? The idea of use is to bind a global variable to your anonymous function's scope.

Ben Over a year ago

@kba +1. to be accurate, it binds a variable from the calling scope (global here is a bit ambiguous)

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