Initial data commit

Task/Y-combinator/PHP/y-combinator-1.php

@@ -0,0 +1,22 @@
+<?php
+function Y($f) {
+  $g = function($w) use($f) {
+    return $f(function() use($w) {
+      return call_user_func_array($w($w), func_get_args());
+    });
+  };
+  return $g($g);
+}
+
+$fibonacci = Y(function($f) {
+  return function($i) use($f) { return ($i <= 1) ? $i : ($f($i-1) + $f($i-2)); };
+});
+
+echo $fibonacci(10), "\n";
+
+$factorial = Y(function($f) {
+  return function($i) use($f) { return ($i <= 1) ? 1 : ($f($i - 1) * $i); };
+});
+
+echo $factorial(10), "\n";
+?>

Task/Y-combinator/PHP/y-combinator-2.php

@@ -0,0 +1,5 @@
+function Y($f) {
+  return function() use($f) {
+    return call_user_func_array($f(Y($f)), func_get_args());
+  };
+}

Task/Y-combinator/PHP/y-combinator-3.php

@@ -0,0 +1,26 @@
+<?php
+function Y($f) {
+  $g = create_function('$w', '$f = '.var_export($f,true).';
+    return $f(create_function(\'\', \'$w = \'.var_export($w,true).\';
+      return call_user_func_array($w($w), func_get_args());
+    \'));
+  ');
+  return $g($g);
+}
+
+function almost_fib($f) {
+  return create_function('$i', '$f = '.var_export($f,true).';
+    return ($i <= 1) ? $i : ($f($i-1) + $f($i-2));
+  ');
+};
+$fibonacci = Y('almost_fib');
+echo $fibonacci(10), "\n";
+
+function almost_fac($f) {
+  return create_function('$i', '$f = '.var_export($f,true).';
+    return ($i <= 1) ? 1 : ($f($i - 1) * $i);
+  ');
+};
+$factorial = Y('almost_fac');
+echo $factorial(10), "\n";
+?>

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";
+?>