void printraw(std::ostream & os) const;
void printtree(std::ostream & os, unsigned indent) const;
void print(std::ostream & os, unsigned upper_precedence=0) const;
bool info(unsigned inf) const;
ex eval(int level=0) const;
protected:
void printraw(std::ostream & os) const;
void printtree(std::ostream & os, unsigned indent) const;
void print(std::ostream & os, unsigned upper_precedence=0) const;
bool info(unsigned inf) const;
ex eval(int level=0) const;
protected: