framework/i18n/MessageFormatter.php
protected function fallbackFormat($pattern, $args, $locale)
    {
        if (($tokens = self::tokenizePattern($pattern)) === false) {
            $this->_errorCode = -1;
            $this->_errorMessage = 'Message pattern is invalid.';

            return false;
        }
        foreach ($tokens as $i => $token) {
            if (is_array($token)) {
                if (($tokens[$i] = $this->parseToken($token, $args, $locale)) === false) {
                    $this->_errorCode = -1;
                    $this->_errorMessage = 'Message pattern is invalid.';

                    return false;
                }
            }
        }

        return implode('', $tokens);
    }
protected function fallbackFormat($pattern, $args, $locale)
    {
        if (($tokens = self::tokenizePattern($pattern)) === false) {
            $this->_errorCode = -1;
            $this->_errorMessage = 'Message pattern is invalid.';

            return false;
        }
        foreach ($tokens as $i => $token) {
            if (is_array($token)) {
                if (($tokens[$i] = $this->parseToken($token, $args, $locale)) === false) {
                    $this->_errorCode = -1;
                    $this->_errorMessage = 'Message pattern is invalid.';

                    return false;
                }
            }
        }

        return implode('', $tokens);
    }
Fallback implementation for MessageFormatter::formatMessage.
@param string $pattern The pattern string to insert things into.
@param array $args The array of values to insert into the format string
@param string $locale The locale to use for formatting locale-dependent parts
@return false|string The formatted pattern string or `false` if an error occurred