implemented relational::subs()

[ginac.git] / ginac / relational.h

diff --git a/ginac/relational.h b/ginac/relational.h
index b04d11c70de99003c33816b8c9e947f55e648941..ed3dbff6abba7b13ee61d3980527ef8b84805f2f 100644 (file)
--- a/ginac/relational.h
+++ b/ginac/relational.h
@@ -3,7 +3,7 @@
  *  Interface to relations between expressions. */
 
 /*
- *  GiNaC Copyright (C) 1999-2001 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2003 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
@@ -54,12 +54,14 @@ public:
        void print(const print_context & c, unsigned level = 0) const;
        unsigned precedence(void) const {return 20;}
        bool info(unsigned inf) const;
-       unsigned nops() const;
-       ex & let_op(int i);
+       size_t nops() const;
+       ex op(size_t i) const;
+       ex map(map_function & f) const;
+       ex subs(const lst & ls, const lst & lr, unsigned options = 0) const;
        ex eval(int level=0) const;
-       ex simplify_ncmul(const exvector & v) const;
 
 protected:
+       ex eval_ncmul(const exvector & v) const;
        bool match_same_type(const basic & other) const;
        unsigned return_type(void) const;
        unsigned return_type_tinfo(void) const;
@@ -71,9 +73,23 @@ public:
        virtual ex rhs(void) const;
 
        // non-virtual functions in this class
-public:
-       operator bool(void) const;
+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(void) const;
+       safe_bool operator!(void) const;
+
 // member variables
        
 protected:
@@ -90,6 +106,12 @@ template<> inline bool is_exactly_a<relational>(const basic & obj)
        return obj.tinfo()==TINFO_relational;
 }
 
+// inlined functions for efficiency
+inline relational::safe_bool relational::operator!() const
+{
+       return make_safe_bool(!static_cast<bool>(*this));
+}
+
 } // namespace GiNaC
 
 #endif // ndef __GINAC_RELATIONAL_H__