<?php
class Pipeline {
    public static function make_pipeline(...$funcs) {
        return function($arg) use ($funcs) {
            $result = $funcs[0]($arg);
            for ($i = 1; $i < sizeof($funcs); $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