protected function parseClassDefinition(TokenStream $stream)
    {
        $token = $stream->expect(Lexer::TOKEN_NODE);
        $this->nodes[] = new Node(self::NODE_CLASS, $token->getValue());
        if ($this->skip($stream)->is(Lexer::TOKEN_EXTD)) {
            $stream->next();
            $token = $stream->skipType(Lexer::TOKEN_WTSP)->expect(Lexer::TOKEN_NODE);
            $this->nodes[] = new Node(self::NODE_EXTENDS, $token->getValue());
        }
        if ($this->skip($stream)->is(Lexer::TOKEN_IMPL)) {
            $stream->next();
            while (!$stream->is(Lexer::TOKEN_EOL)) {
                if ($stream->is(Lexer::TOKEN_NODE)) {
                    $this->nodes[] = new Node(self::NODE_IMPLEMENTS, $stream->current()->getValue());
                }
                $stream->next();
            }
        }
        $this->parseComment($stream, self::NODE_CLASS_COMMENT);
        $this->status = self::STAT_CLASS_DEFINED;
    }