/** @file relational.h * * Interface to relations between expressions. */ /* * GiNaC Copyright (C) 1999-2022 Johannes Gutenberg University Mainz, Germany * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef GINAC_RELATIONAL_H #define GINAC_RELATIONAL_H #include "basic.h" #include "ex.h" #include "archive.h" namespace GiNaC { /** This class holds a relation consisting of two expressions and a logical * relation between them. */ class relational : public basic { GINAC_DECLARE_REGISTERED_CLASS(relational, basic) // types public: enum operators { equal, not_equal, less, less_or_equal, greater, greater_or_equal }; // other constructors public: relational(const ex & lhs, const ex & rhs, operators oper=equal); // functions overriding virtual functions from base classes public: unsigned precedence() const override {return 20;} bool info(unsigned inf) const override; size_t nops() const override; ex op(size_t i) const override; ex map(map_function & f) const override; ex subs(const exmap & m, unsigned options = 0) const override; /** Save (a.k.a. serialize) object into archive. */ void archive(archive_node& n) const override; /** Read (a.k.a. deserialize) object from archive. */ void read_archive(const archive_node& n, lst& syms) override; ex canonical() const; protected: ex eval_ncmul(const exvector & v) const override; bool match_same_type(const basic & other) const override; unsigned return_type() const override; return_type_t return_type_tinfo() const override; unsigned calchash() const override; // new virtual functions which can be overridden by derived classes protected: void do_print(const print_context & c, unsigned level) const; void do_print_python_repr(const print_python_repr & c, unsigned level) const; public: ex lhs() const { return lh; } ex rhs() const { return rh; } // non-virtual functions in this class private: // For conversions to Boolean, as would be used in an if conditional, // implicit conversions from bool to int have a large number of // undesirable side effects. The following safe_bool type enables // use of relational objects in conditionals without those side effects struct safe_bool_helper { void nonnull() {}; }; typedef void (safe_bool_helper::*safe_bool)(); safe_bool make_safe_bool(bool) const; public: operator safe_bool() const; safe_bool operator!() const; // member variables protected: ex lh; ex rh; operators o; }; GINAC_DECLARE_UNARCHIVER(relational); // utility functions // inlined functions for efficiency inline relational::safe_bool relational::operator!() const { return make_safe_bool(!static_cast(*this)); } } // namespace GiNaC #endif // ndef GINAC_RELATIONAL_H