3 * Interface to relations between expressions. */
6 * GiNaC Copyright (C) 1999-2010 Johannes Gutenberg University Mainz, Germany
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
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14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
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23 #ifndef GINAC_RELATIONAL_H
24 #define GINAC_RELATIONAL_H
32 /** This class holds a relation consisting of two expressions and a logical
33 * relation between them. */
34 class relational : public basic
36 GINAC_DECLARE_REGISTERED_CLASS(relational, basic)
51 relational(const ex & lhs, const ex & rhs, operators oper=equal);
53 // functions overriding virtual functions from base classes
55 unsigned precedence() const {return 20;}
56 bool info(unsigned inf) const;
58 ex op(size_t i) const;
59 ex map(map_function & f) const;
60 ex subs(const exmap & m, unsigned options = 0) const;
61 ex eval(int level=0) const;
63 /** Save (a.k.a. serialize) object into archive. */
64 void archive(archive_node& n) const;
65 /** Read (a.k.a. deserialize) object from archive. */
66 void read_archive(const archive_node& n, lst& syms);
68 ex eval_ncmul(const exvector & v) const;
69 bool match_same_type(const basic & other) const;
70 unsigned return_type() const;
71 return_type_t return_type_tinfo() const;
72 unsigned calchash() const;
74 // new virtual functions which can be overridden by derived classes
76 void do_print(const print_context & c, unsigned level) const;
77 void do_print_python_repr(const print_python_repr & c, unsigned level) const;
80 virtual ex lhs() const;
81 virtual ex rhs() const;
83 // non-virtual functions in this class
85 // For conversions to boolean, as would be used in an if conditional,
86 // implicit conversions from bool to int have a large number of
87 // undesirable side effects. The following safe_bool type enables
88 // use of relational objects in conditionals without those side effects
89 struct safe_bool_helper {
93 typedef void (safe_bool_helper::*safe_bool)();
95 safe_bool make_safe_bool(bool) const;
98 operator safe_bool() const;
99 safe_bool operator!() const;
108 GINAC_DECLARE_UNARCHIVER(relational);
112 // inlined functions for efficiency
113 inline relational::safe_bool relational::operator!() const
115 return make_safe_bool(!static_cast<bool>(*this));
120 #endif // ndef GINAC_RELATIONAL_H