spot
0.9.1
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00001 // Copyright (C) 2009, 2010, 2012 Laboratoire de Recherche et 00002 // Développement de l'Epita (LRDE). 00003 // Copyright (C) 2003, 2004 Laboratoire d'Informatique de Paris 6 (LIP6), 00004 // 00005 // This file is part of Spot, a model checking library. 00006 // 00007 // Spot is free software; you can redistribute it and/or modify it 00008 // under the terms of the GNU General Public License as published by 00009 // the Free Software Foundation; either version 2 of the License, or 00010 // (at your option) any later version. 00011 // 00012 // Spot is distributed in the hope that it will be useful, but WITHOUT 00013 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 00014 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 00015 // License for more details. 00016 // 00017 // You should have received a copy of the GNU General Public License 00018 // along with Spot; see the file COPYING. If not, write to the Free 00019 // Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 00020 // 02111-1307, USA. 00021 00024 #ifndef SPOT_LTLAST_CONSTANT_HH 00025 # define SPOT_LTLAST_CONSTANT_HH 00026 00027 #include "formula.hh" 00028 00029 namespace spot 00030 { 00031 namespace ltl 00032 { 00033 00036 class constant : public formula 00037 { 00038 public: 00039 enum type { False, True, EmptyWord }; 00040 virtual void accept(visitor& v) const; 00041 00043 type val() const; 00045 const char* val_name() const; 00046 00047 virtual std::string dump() const; 00048 00050 static constant* true_instance() { return &true_instance_; } 00052 static constant* false_instance() { return &false_instance_; } 00054 static constant* empty_word_instance() { return &empty_word_instance_; } 00055 00056 protected: 00057 constant(type val); 00058 virtual ~constant(); 00059 00060 private: 00061 type val_; 00062 00063 static constant true_instance_; 00064 static constant false_instance_; 00065 static constant empty_word_instance_; 00066 // If you add new constants here, be sure to update the 00067 // formula::formula() constructor. 00068 }; 00069 00070 00075 inline 00076 const constant* 00077 is_constant(const formula* f) 00078 { 00079 if (f->kind() != formula::Constant) 00080 return 0; 00081 return static_cast<const constant*>(f); 00082 } 00083 } 00084 } 00085 00086 #endif // SPOT_LTLAST_CONSTANT_HH