Как правильно загружать шаблоны?

<?php

class Templates {

    var $directory = '';
    var $template = null;
    var $copy_template = null;
    var $data = array ();
    var $block = array ();
    var $result = array ('css' => '', 'js' => '', 'content' => '' );

    function set($name, $value) {
        if( is_array( $value ) ) {
            if( count( $value ) ) {
                foreach ( $value as $key => $key_var ) {
                    $this->set( $key, $key_var );
                }
            }
            return;
        }
        $this->data[$name] = $value;
    }

    function block($name, $value) {
        if( is_array( $value ) ) {
            if( count( $value ) ) {
                foreach ( $value as $key => $key_var ) {
                    $this->block( $key, $key_var );
                }
            }
            return;
        }
        $this->block[$name] = $value;
    }

    function template($tpl_name) {
        if( $tpl_name == '' || !file_exists( $this->directory.$tpl_name.".tpl") ) {
            $this->template = "Template not found: " .str_replace(ROOT, '', $this->directory).$tpl_name.".tpl";
            $this->copy_template = $this->template;
            return "";
        }
        $this->template = file_get_contents( $this->directory.$tpl_name.".tpl");
        $this->copy_template = $this->template;
        return true;
    }

    function _clear() {

        $this->data = array ();
        $this->block = array ();
        $this->copy_template = $this->template;

    }

    function clear() {

        $this->data = array ();
        $this->block = array ();
        $this->copy_template = null;
        $this->template = null;

    }

    function global_clear() {

        $this->data = array ();
        $this->block = array ();
        $this->result = array ();
        $this->copy_template = null;
        $this->template = null;

    }

    function compile($tpl) {

        if( count( $this->block ) ) {
            foreach ( $this->block as $key_find => $key_replace ) {
                $find_preg[] = $key_find;
                $replace_preg[] = $key_replace;
            }

            $this->copy_template = preg_replace( $find_preg, $replace_preg, $this->copy_template );
        }

        foreach ( $this->data as $key_find => $key_replace ) {
            $find[] = $key_find;
            $replace[] = $key_replace;
        }

        $this->copy_template = str_ireplace( $find, $replace, $this->copy_template );

        if( isset( $this->result[$tpl] ) ) $this->result[$tpl] .= $this->copy_template;
        else $this->result[$tpl] = $this->copy_template;

        $this->_clear();
    }

};