3 * Interface to relations between expressions. */
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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 override {return 20;}
56 bool info(unsigned inf) const override;
57 size_t nops() const override;
58 ex op(size_t i) const override;
59 ex map(map_function & f) const override;
60 ex subs(const exmap & m, unsigned options = 0) const override;
62 /** Save (a.k.a. serialize) object into archive. */
63 void archive(archive_node& n) const override;
64 /** Read (a.k.a. deserialize) object from archive. */
65 void read_archive(const archive_node& n, lst& syms) override;
67 ex eval_ncmul(const exvector & v) const override;
68 bool match_same_type(const basic & other) const override;
69 unsigned return_type() const override;
70 return_type_t return_type_tinfo() const override;
71 unsigned calchash() const override;
73 // new virtual functions which can be overridden by derived classes
75 void do_print(const print_context & c, unsigned level) const;
76 void do_print_python_repr(const print_python_repr & c, unsigned level) const;
79 ex lhs() const { return lh; }
80 ex rhs() const { return rh; }
82 // non-virtual functions in this class
84 // For conversions to Boolean, as would be used in an if conditional,
85 // implicit conversions from bool to int have a large number of
86 // undesirable side effects. The following safe_bool type enables
87 // use of relational objects in conditionals without those side effects
88 struct safe_bool_helper {
92 typedef void (safe_bool_helper::*safe_bool)();
94 safe_bool make_safe_bool(bool) const;
97 operator safe_bool() const;
98 safe_bool operator!() const;
107 GINAC_DECLARE_UNARCHIVER(relational);
111 // inlined functions for efficiency
112 inline relational::safe_bool relational::operator!() const
114 return make_safe_bool(!static_cast<bool>(*this));
119 #endif // ndef GINAC_RELATIONAL_H