ex diff(const symbol & s, unsigned nth=1) const;
int compare(const basic & other) const;
bool is_equal(const basic & other) const;
const basic & hold(void) const;
unsigned gethash(void) const { if (flags & status_flags::hash_calculated) return hashvalue; else return calchash(); }
unsigned tinfo(void) const {return tinfo_key;}
ex diff(const symbol & s, unsigned nth=1) const;
int compare(const basic & other) const;
bool is_equal(const basic & other) const;
const basic & hold(void) const;
unsigned gethash(void) const { if (flags & status_flags::hash_calculated) return hashvalue; else return calchash(); }
unsigned tinfo(void) const {return tinfo_key;}