PHP设计模式之解释器模式

解释器： 解释器设计模式用于分析一个实体的关键元素，并且针对每个元素都提供自己的解释或相应的动作。
解释器设计模式最常用于PHP/HTML 模板系统。


    class User {   
        protected $_username = "";   
        public function __construct($username) {   
            $this->_username = $username;   
        }  
        public function getProfilePage() {   
            $profile  = "
I like Never Again ! 
";   
            $profile .= "I love all of their songs. My favorite CD: 
";   
            $profile .= "{{myCD.getTitle}}!!";   
               
            return $profile;   
        }   
    }   
    class userCD {   
        public function setUser(User $user) {   
            $this->_user = $user;   
        }   
        public function getTitle() {   
            $title = "Waste of a Rib";   
            return $title;   
        }   
    }   
    class userCDInterpreter {   
           
        protected $_user = NULL;   
           
        public function setUser(User $user) {   
            $this->_user = $user;   
        }   
           
        public function getInterpreted() {   
            $profile = $this->_user->getProfilePage();   
               
            if (preg_match_all('/\{\{myCD\.(.*?)\}\}/', $profile, $triggers, PREG_SET_ORDER)) {   
                $replacements = array();   
                   
                foreach ($triggers as $trigger) {   
                    $replacements[] = $trigger[1];   
                }   
                   
                $replacements = array_unique($replacements);   
                   
                $myCD = new userCD();   
                $myCD->setUser($this->_user);   
                   
                foreach ($replacements as $replacement) {   
                    $profile = str_replace("{{myCD.{$replacement}}}", call_user_func(array($myCD, $replacement)), $profile);   
                }   
            }   
               
            return $profile;   
        }   
           
    }   
    $username = "aaron";   
    $user = new User($username);   
    $interpreter = new userCDInterpreter();   
    $interpreter->setUser($user);   
       
    print "
{$username}'s Profile
";   
    print $interpreter->getInterpreted();   
?> 

数据库脚本请参照：http://www.cxybl.com/html/wlbc/Php/2011_1126_9458.html