Question

for example I need some code like:

if(need_params('function_name')):
    print 'function_name($params)';
else
    print 'function_name()';
endif;

Answer 1

You should have a look into the ReflectionFunction Class.

<?php
function need_params($func) {
    $reflection = new ReflectionFunction($func);

    return $reflection->getNumberOfParameters();
}

// use
function foo($arg) {}

echo need_params('foo') > 0 ? 'Needs params' : 'No params';
?>