php bind variable to function's scope in older PHP - php

Question

I would like to bind a variable to a function's scope, I can do this in php use the 'use' keyword after PHP 5.3, however how do I do the equivalent in versions < PHP 5.3?
test_use_keyword();
function test_use_keyword(){
$test =2;
$res=array_map(
function($el) use ($test){
return $el * $test;
},
array(3)
);
print_r($res);
}

Answer 1

You can use a global variable, but you should always avoid globals variables whereever possible. As a suggestion, without knowing, what you are trying to solve with this
class Xy ( {
private $test;
public function __construct ($test) {
$this->test = $test;
}
public function call ($el) {
return $el * $this->test;
}
}
print_r(array_map(array(new Xy(2), 'call'), array(3));
Also possible are the good old lambdas
$test = 2;
$a = create_function ('$el', 'return $el * ' . $test . ';');
print_r (array_map($a, array(3)));

Answer 2

Normally through globals, seriously. Although hacks could be used to mimic the functionality, like partial functions in php. Extracted from article:
function partial()
{
if(!class_exists('partial'))
{
class partial{
var $values = array();
var $func;
function partial($func, $args)
{
$this->values = $args;
$this->func = $func;
}
function method()
{
$args = func_get_args();
return call_user_func_array($this->func, array_merge($args, $this->values));
}
}
}
//assume $0 is funcname, $1-$x is partial values
$args = func_get_args();
$func = $args[0];
$p = new partial($func, array_slice($args,1));
return array($p, 'method');
}
And only after that could you have something like.
function multiply_by($base, $value) {
return $base * $value;
}
// ...
$res = array_map(partial("multiply_by", $test), array(3));
Not... worth... it.