Currying: Difference between revisions

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@@ Line 1,325: / Line 1,325: @@
 <lang php><?php
-function product_curryied($a)
+function curry($callable)
 {
-    return function($b) use($a) {
+    if (_number_of_required_params($callable) === 0) {
-        return $a * $b;
+        return _make_function($callable);
+    }
+    if (_number_of_required_params($callable) === 1) {
+        return _curry_array_args($callable, _rest(func_get_args()));
+    }
+    return _curry_array_args($callable, _rest(func_get_args()));
+}
+function _curry_array_args($callable, $args, $left = true)
+{
+    return function () use ($callable, $args, $left) {
+        if (_is_fullfilled($callable, $args)) {
+            return _execute($callable, $args, $left);
+        }
+        $newArgs = array_merge($args, func_get_args());
+        if (_is_fullfilled($callable, $newArgs)) {
+            return _execute($callable, $newArgs, $left);
+        }
+        return _curry_array_args($callable, $newArgs, $left);
     };
 }
+function _number_of_required_params($callable)
-echo json_encode(array_map(product_curryied(7), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]));</lang>
+{
+    if (is_array($callable)) {
+        $refl = new \ReflectionClass($callable[0]);
+        $method = $refl->getMethod($callable[1]);
+        return $method->getNumberOfRequiredParameters();
+    }
+    $refl = new \ReflectionFunction($callable);
+    return $refl->getNumberOfRequiredParameters();
+}
+function _make_function($callable)
+{
+    if (is_array($callable))
+        return function() use($callable) {
+            return call_user_func_array($callable, func_get_args());
+        };
+    return $callable;
+}
+function _execute($callable, $args, $left)
+{
+    if (! $left) {
+        $args = array_reverse($args);
+    }
+    $placeholders = _placeholder_positions($args);
+    if (0 < count($placeholders)) {
+        $n = _number_of_required_params($callable);
+        if ($n <= _last($placeholders[count($placeholders) - 1])) {
+            throw new \Exception('Argument Placeholder found on unexpected position!');
+        }
+        foreach ($placeholders as $i) {
+            $args[$i] = $args[$n];
+            array_splice($args, $n, 1);
+        }
+    }
+    return call_user_func_array($callable, $args);
+}
+function _placeholder_positions($args)
+{
+    return array_keys(array_filter($args, '_is_placeholder'));
+}
+function _is_fullfilled($callable, $args)
+{
+    $args = array_filter($args, function($arg) {
+        return ! _is_placeholder($arg);
+    });
+    return count($args) >= _number_of_required_params($callable);
+}
+function _is_placeholder($arg)
+{
+    return $arg instanceof Placeholder;
+}
+function _rest(array $args)
+{
+    return array_slice($args, 1);
+}
+function product($a, $b)
+{
+    return $a * $b;
+}
+echo json_encode(array_map(curry('product', 7), [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]));</lang>
 {{out}}<pre>[7,14,21,28,35,42,49,56,63,70]</pre>