<?php
class Pipeline
{
    public static function make_pipeline(...$funcs)
    {
        return function($arg) use ($funcs)
        {
            $fn_num = sizeof($funcs);
            $result = $arg;
            for ($i = 0; $i < $fn_num; $i++){
                $result = $funcs[$i]($result);
            }
            return $result;
        };
    }
}

$fun = Pipeline::make_pipeline(function($x) { return $x * 3; }, function($x) { return $x + 1; },
                          function($x) { return $x / 2; });
echo $fun(3); # should print 5