a mechanism for code reuse in single inheritance languages

 1 <?php
 2 class Base {
 3     public function sayHello() {
 4         echo ‘Hello‘;
 5     }
 6 }
 7 
 8 trait SayWorld {
 9     public function sayHello() {
10         parent :: sayHello();
11         echo ‘World!‘;
12     }
13 }
14 
15 class MyHelloWorld extends Base {
16     use SayWorld;
17 }
18 
19 $o = new MyHelloWorld();
20 $o->sayHello();
21 
22 
23 
24 trait HelloWorld {
25     public function sayHello() {
26         echo ‘Hello World‘;
27     }
28 }
29 class TheWorldIsNotEnough {
30     use HelloWorld;
31     public function sayHello() {
32         echo ‘Hello Universe!‘;
33     }
34 }
35 
36 $ob = new TheWorldIsNotEnough();
37 $ob->sayHello();
38 
39 trait Hello {
40     public function sayHello() {
41         echo ‘Hello‘;
42     }
43 }
44 
45 trait World {
46     public function sayWorld() {
47         echo ‘World‘;
48     }
49 }
50 
51 class MyHelloWorld_c {
52     use Hello, World;
53     public function sayExclamationMark() {
54         echo ‘!‘;
55     }
56 }
57 
58 $oc = new MyHelloWorld_c();
59 $oc->sayHello();
60 $oc->sayWorld();
61 $oc->sayExclamationMark();