Question

I am using ‘filter_var()’ function with FILTER_CALLBACK.
Something like this:

$value = filter_var($value, FILTER_CALLBACK, array('options' => 'my_func'));

my_func() usually receives the $value as an argument:

function my_func($val)
{
    if (some cond)
    {
        return $val;
    }
    else
    {
        return false;
    }
}  

Now I want to use another $var in my_func() from the outer scope (I mean with the filter_var()).
One option is to declare it as global in the function. Another is to pass it as argument.
How can I avoid declaring global and pass the $var as argument?

Answer 1

If you’re using PHP 5.3+, you could use closures:

function my_func($val, $arg1, $arg2)
{
    return $arg1.': '.$val.' '.$arg2;
}

$testVar = 'test';
$result = filter_var($testVar, FILTER_CALLBACK, array('options' => function($var) {
    return my_func($var, 'someValue', 'someOtherValue');
}));

var_dump($result); // string(30) "someValue: test someOtherValue"

Of course, this example doesn’t really “validate” anything, just changes the text a bit, but it should give you an idea of how it works.

EDIT: Judging from the comments, you want to use a certain function for certain values without checking which one to use at each loop. Have you considered using call_user_func? Here’s an example:

function myFunc1($arg1, $arg2) { return 'Executed myFunc1 with arguments: '.$arg1.' '.$arg2; }
function myFunc2($arg1, $arg2) { return 'Executed myFunc2 with arguments: '.$arg1.' '.$arg2; }

$functionsToUse = array(
    'myFunc1',
    'myFunc2'
);

foreach ($functionsToUse as $func)
{
    echo call_user_func($func, 'value', 'another value').'<br>';
}