How can I use this extended template parser class for CodeIgniter? - php

Question

I've been searching around for extensions of CodeIgniter's parser class that would add the use of conditional statements in the view files. The problem is that the location that I've found it at doesn't offer any explanation on how to use it and doesn't list anything about the file's author. Could anyone perhaps share any thoughts on this code?
<?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;
}
}