1: <?php
 2: 
 3: namespace Alchemy\util;
 4: 
 5: 
 6: /**
 7:  * Allow method chaining and simulated object immutablity
 8:  * by performing every method call on a clone of the object
 9:  * you started with.
10:  */
11: class Monad {
12:     protected $value;
13: 
14: 
15:     /**
16:      * Object constructor.
17:      *
18:      * @param Object $value Object to wrap
19:      */
20:     public function __construct($value) {
21:         $this->value = $value;
22:     }
23: 
24: 
25:     /**
26:      * Clone the inner object, call a method on it, and return it
27:      *
28:      * @param string $fn Method Name
29:      * @param array $args
30:      * @return Monad
31:      */
32:     public function __call($fn, $args) {
33:         $that = clone $this;
34: 
35:         $method = array($that->value, $fn);
36:         $value = call_user_func_array($method, $args);
37:         $cls = get_class($this->value);
38: 
39:         // Returned nothing, is probably just did internal mutation
40:         if ($value instanceof $cls) {
41:             $that->value = $value;
42:             return $that;
43:         }
44: 
45:         // Returned a value to send to the user
46:         if (!is_null($value)) {
47:             return $value;
48:         }
49: 
50:         return $that;
51:     }
52: 
53: 
54:     /**
55:      * Force PHP to deep clone
56:      */
57:     public function __clone() {
58:         $this->value = clone $this->value;
59:     }
60: 
61: 
62:     /**
63:      * Unwrap the value
64:      *
65:      * @return mixed
66:      */
67:     public function unwrap() {
68:         return clone $this->value;
69:     }
70: }
71: