<?php
class Pipeline
{
    public static function make_pipeline()
    {

    	$functions = func_get_args();

    	return function($arg) use ($functions) {
    		foreach ($functions as $function) {
    			if(!isset($value)) {
    				$value = $function($arg);
    			} else {
    				$value = $function($value);
    			}
    		}

    		return $value;
    	};


    }
}

$fun = Pipeline::make_pipeline(function($x) { return $x * 3; }, function($x) { return $x + 1; },
                          function($x) { return $x / 2; });

echo $fun(3); # should print 5