3v4l.org

run code in 300+ PHP versions simultaneously
<?php function grammar($description) { $g=array(); foreach(explode("\n",$description) as $line) { $sides = explode(" => ",$line); $lhs = $sides[0]; $rhs = $sides[1]; $alternatives = explode(' | ',$rhs); $g[$lhs] = array(array_map("explode",$alternatives,array(" "))); } return $g; } $des =<<<G Exp => Term [+-] Exp | Term G; print_r(grammar($des));

preferences:
35.99 ms | 402 KiB | 5 Q