3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?hh $zero = $f ==> $x ==> $x; $one = $f ==> $x ==> $f($x); $two = $f ==> $x ==> $f($f($x)); $three = $f ==> $x ==> $f($f($f($x))); $five = $f ==> $x ==> $f($f($f($f($f($x))))); $true = $x ==> $y ==> $x; $false = $x ==> $y ==> $y; $if = $f ==> $f; $isZero = $f ==> ($f($x ==> $false))($true); $increment = $n ==> $f ==> $x ==> $f(($n($f))($x)); $decrement = $n ==> $f ==> $x ==> (($n($g ==> $h ==> $h($g($f))))($y ==> $x))($y ==> $y); $add = $m ==> $n ==> ($n($increment))($m); $subtract = $m ==> $n ==> ($n($decrement))($m); $multiply = $m ==> $n ==> ($n($add($m)))($zero); $power = $m ==> $n ==> ($n($multiply($m)))($one); $pair = $x ==> $y ==> $f ==> ($f($x))($y); $car = $p ==> $p($x ==> $y ==> $x); $cdr = $p ==> $p($x ==> $y ==> $y); $toNum = $f ==> ($f($x ==> $x + 1))(0); $toBool = $f ==> (($if($f))(true))(false); $toTextBool = $f ==> $toBool($f) ? 'true' : 'false'; echo $toTextBool($isZero($zero));
based on PAK4B
Output for 5.4.0 - 5.4.32
<?hh $zero = $f ==> $x ==> $x; $one = $f ==> $x ==> $f($x); $two = $f ==> $x ==> $f($f($x)); $three = $f ==> $x ==> $f($f($f($x))); $five = $f ==> $x ==> $f($f($f($f($f($x))))); $true = $x ==> $y ==> $x; $false = $x ==> $y ==> $y; $if = $f ==> $f; $isZero = $f ==> ($f($x ==> $false))($true); $increment = $n ==> $f ==> $x ==> $f(($n($f))($x)); $decrement = $n ==> $f ==> $x ==> (($n($g ==> $h ==> $h($g($f))))($y ==> $x))($y ==> $y); $add = $m ==> $n ==> ($n($increment))($m); $subtract = $m ==> $n ==> ($n($decrement))($m); $multiply = $m ==> $n ==> ($n($add($m)))($zero); $power = $m ==> $n ==> ($n($multiply($m)))($one); $pair = $x ==> $y ==> $f ==> ($f($x))($y); $car = $p ==> $p($x ==> $y ==> $x); $cdr = $p ==> $p($x ==> $y ==> $y); $toNum = $f ==> ($f($x ==> $x + 1))(0); $toBool = $f ==> (($if($f))(true))(false); $toTextBool = $f ==> $toBool($f) ? 'true' : 'false'; echo $toTextBool($isZero($zero));