lib/Twig/lib/Twig/TokenStream.php
public function expect($type, $value = null, $message = null)
    {
        $token = $this->tokens[$this->current];
        if (!$token->test($type, $value)) {
            $line = $token->getLine();
            throw new Twig_Error_Syntax(sprintf('%sUnexpected token "%s" of value "%s" ("%s" expected%s).',
                $message ? $message.'. ' : '',
                Twig_Token::typeToEnglish($token->getType()), $token->getValue(),
                Twig_Token::typeToEnglish($type), $value ? sprintf(' with value "%s"', $value) : ''),
                $line,
                $this->source
            );
        }
        $this->next();

        return $token;
    }
public function expect($type, $value = null, $message = null)
    {
        $token = $this->tokens[$this->current];
        if (!$token->test($type, $value)) {
            $line = $token->getLine();
            throw new Twig_Error_Syntax(sprintf('%sUnexpected token "%s" of value "%s" ("%s" expected%s).',
                $message ? $message.'. ' : '',
                Twig_Token::typeToEnglish($token->getType()), $token->getValue(),
                Twig_Token::typeToEnglish($type), $value ? sprintf(' with value "%s"', $value) : ''),
                $line,
                $this->source
            );
        }
        $this->next();

        return $token;
    }
Tests a token and returns it or throws a syntax error.

@return Twig_Token