PHP functions such as array_map and array_filter take an array, and a function as arguments.
EG:
$result = array_map(function (el) { // do stuff }, $elements) Is it possible to pass a standard php function the same way?
Something along the lines of $result = array_map(boolval, $elements)
EDIT The above example throws the error Undefined constant boolval
You need to pass the function (user-defined OR builtin) name as a string in the parameter of array_map function.
Do the following:
$result = array_map('boolval', $elements); 
$boolval = function($x) { return boolval($x); };. I really can't think of any context where this would be needed, though. A callable type declaration should always convert the string to its corresponding function.Normally, you just run
$result = array_map('functionName', $array); If it's a class function, you have to pass the object instance and the function name in an array.
$result = array_map([$objectInstance, 'functionName'], $array); If the function is in the same class, then
$result = array_map([$this, 'functionName'], $array); When you have any function which take a callable as a parameter PHP function is passed by its name as a string. And any PHP built-in or user-defined function can be used, except language constructs such as: array(), echo, empty(), eval(), exit(), isset(), list(), print or unset(). You can read more here PHP Callbacks/Callables.
You can call any function by passing it name as a first parameter of call_user_func_array and second parameters an array with parameters that the function you want to call take
$result = call_user_func_array('array_map', array( 'boolval', array( "1", '0', true, false ) )); 
boolval$result = array_map('boolval', $elements);