Initial data commit

Task/Y-combinator/PHP/y-combinator-4.php

@@ -0,0 +1,20 @@
+<?php
+function pseudoY($f) {
+    $g = function($w) use ($f) {
+        return $f->bindTo(function() use ($w) {
+            return call_user_func_array($w($w), func_get_args());
+        });
+    };
+    return $g($g);
+}
+
+$factorial = pseudoY(function($n) {
+    return $n > 1 ? $n * $this($n - 1) : 1;
+});
+echo $factorial(10), "\n";
+
+$fibonacci = pseudoY(function($n) {
+    return $n > 1 ? $this($n - 1) + $this($n - 2) : $n;
+});
+echo $fibonacci(10), "\n";
+?>