public function trigger_template_error($args = null, $line = null)
    {
        // get template source line which has error
        if (!isset($line)) {
            $line = $this->lex->line;
        }
        $match = preg_split("/\n/", $this->lex->data);
        $error_text = 'Syntax Error in template "' . $this->template->source->filepath . '"  on line ' . $line . ' "' . htmlspecialchars(trim(preg_replace('![\t\r\n]+!',' ',$match[$line-1]))) . '" ';
        if (isset($args)) {
            // individual error message
            $error_text .= $args;
        } else {
            // expected token from parser
            $error_text .= ' - Unexpected "' . $this->lex->value.'"';
            if (count($this->parser->yy_get_expected_tokens($this->parser->yymajor)) <= 4 ) {
                foreach ($this->parser->yy_get_expected_tokens($this->parser->yymajor) as $token) {
                    $exp_token = $this->parser->yyTokenName[$token];
                    if (isset($this->lex->smarty_token_names[$exp_token])) {
                        // token type from lexer
                        $expect[] = '"' . $this->lex->smarty_token_names[$exp_token] . '"';
                    } else {
                        // otherwise internal token name
                        $expect[] = $this->parser->yyTokenName[$token];
                    }
                }
                $error_text .= ', expected one of: ' . implode(' , ', $expect);
            }
        }
        throw new SmartyCompilerException($error_text);
    }