如何为CodeIgniter使用此扩展模板解析器类？

Question

我一直在寻找CodeIgniter解析器类的扩展，它将在视图文件中添加条件语句。问题是，我发现它的location并没有提供有关如何使用它的任何解释，也没有列出该文件作者的任何内容。任何人都可以分享对此代码的任何想法吗？

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package     CodeIgniter
 * @author      ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2008, EllisLab, Inc.
 * @license     http://codeigniter.com/user_guide/license.html
 * @link        http://codeigniter.com
 * @since       Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * MY Parser Class
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @category    Parser
 * @author      Haloweb Ltd
 */

class MY_Parser extends CI_Parser {

    /**
     *  Parse a template
     *
     * Parses pseudo-variables contained in the specified template,
     * replacing them with the data in the second param
     *
     * @access  public
     * @param   string
     * @param   array
     * @param   bool
     * @return  string
    */

    function parse($template, $data, $return = FALSE, $include = FALSE)
    {   
        $CI =& get_instance();

        if ($template == '')
        {
            return FALSE;
        }

        if ($include === FALSE)
        {       
            $template = $CI->load->view($template, $data, TRUE);
        }

        if (isset($data) && $data != '')
        {
            foreach ($data as $key => $val)
            {
                if (is_array($val))
                {
                    $template = $this->_parse_pair($key, $val, $template);      
                }
                else
                {
                    $template = $this->_parse_single($key, (string)$val, $template);
                }
            }
        }

        // Check for conditional statments
        $template = $this->conditionals($template, $data);

        // populate form tags
        preg_match_all('/{form:(.+)}/i', $template, $posts);
        if ($posts)
        {
            foreach ($posts[1] as $post => $value)
            {
                if ($postValue = $CI->input->post($value))
                {
                    $template = str_replace('{form:'.$value.'}', $postValue, $template);
                }
                else
                {
                    $template = str_replace('{form:'.$value.'}', '', $template);
                }
            }
        }

        //$template = preg_replace('/{(.+)}/i', '', $template);

        if ($return == FALSE)
        {
            $CI->output->append_output($template);
        }

        return $template;
    }

    // --------------------------------------------------------------------

    /**
     *  Parse conditional statments
     * 
     * @access    public
     * @param    string
     * @param    bool
     * @return    string
    */

    function conditionals($template, $data)
    {
        if (preg_match_all('/'.$this->l_delim.'if (.+)'.$this->r_delim.'(.+)'.$this->l_delim.'\/if'.$this->r_delim.'/siU', $template, $conditionals, PREG_SET_ORDER))
        {
            if (count($conditionals) > 0)
            {
                // filter through conditionals
                foreach($conditionals as $condition)
                {
                    // get conditional and the string inside
                    $code = (isset($condition[0])) ? $condition[0] : FALSE;
                    $condString = (isset($condition[1])) ? str_replace(' ', '', $condition[1]) : FALSE;
                    $insert = (isset($condition[2])) ? $condition[2] : '';

                    // check code is valid
                    if (!preg_match('/('.$this->l_delim.'|'.$this->r_delim.')/', $condString, $condProblem))
                    {
                        if (!empty($code) || $condString != FALSE || !empty($insert))
                        {
                            if (preg_match("/^!(.*)$/", $condString, $matches))
                            {
                                $condVar = (@!$data[trim($matches[1])]) ? 0 : $data[trim($matches[1])];

                                @$result = (!$condVar) ? TRUE : FALSE;
                            }
                            elseif (preg_match("/([a-z0-9\-_:\(\)]+)(\!=|=|==|>|<)([a-z0-9\-_\/]+)/", $condString, $matches))
                            {
                                $condVar = (@!$data[$matches[1]]) ? 0 : $data[trim($matches[1])];

                                if ($matches[2] == '==' || $matches[2] == '=')
                                {
                                    @$result = ($condVar === $matches[3]) ? TRUE : FALSE;
                                }
                                elseif ($matches[2] == '!=')
                                {
                                    @$result = ($condVar !== $matches[3]) ? TRUE : FALSE;
                                }
                                elseif ($matches[2] == '>')
                                {
                                    @$result = ($condVar > $matches[3]) ? TRUE : FALSE;
                                }
                                elseif ($matches[2] == '<')
                                {
                                    @$result = ($condVar < $matches[3]) ? TRUE : FALSE;
                                }                           
                            }
                            else
                            {
                                // if the variable is set
                                if (isset($data[$condString]) && is_array($data[$condString]))
                                {
                                    $result = (count($data[$condString]) > 0) ? TRUE : FALSE;                           
                                }
                                else
                                {
                                    $result = (isset($data[$condString]) && $data[$condString] != '') ? TRUE : FALSE;
                                }
                            }

                            // filter for else
                            $insert = preg_split('/'.$this->l_delim.'else'.$this->r_delim.'/siU', $insert);

                            if ($result == TRUE)
                            {
                                // show the string inside
                                $template = str_replace($code, $insert[0], $template);
                            }
                            else
                            {
                                if (is_array($insert))
                                {
                                    $insert = (isset($insert[1])) ? $insert[1] : '';
                                    $template = str_replace($code, $insert, $template);
                                }
                                else
                                {
                                    $template = str_replace($code, '', $template);
                                }
                            }
                        }
                    }
                    else
                    {
                        // remove any conditionals we cant process
                        $template = str_replace($code, '', $template);
                    }
                }
            }                   

            //print_r($conditionals);
        }

        return $template;
    }

    // --------------------------------------------------------------------

    /**
     *  Matches a variable pair
     *
     * @access  private
     * @param   string
     * @param   string
     * @return  mixed
     */ 

    function _match_pair($string, $variable)
    {
        $variable = str_replace('(', '\(', $variable);
        $variable = str_replace(')', '\)', $variable);      

        if ( ! preg_match("|".$this->l_delim . $variable . $this->r_delim."(.+?)".$this->l_delim . '/' . $variable . $this->r_delim."|s", $string, $match))
        {
            return FALSE;
        }

        return $match;
    }   

}