int ldegree(const ex & s) const override;
ex coeff(const ex & s, int n = 1) const override;
bool has(const ex & other, unsigned options = 0) const override;
- ex eval(int level=0) const override;
+ ex eval() const override;
ex evalf(int level=0) const override;
ex real_part() const override;
ex imag_part() const override;