not.hh

00001 // This file is a part of Aurelia.
00002 // Copyright (C) 2010  Valentin David
00003 // Copyright (C) 2010  University of Bergen
00004 //
00005 // This program is free software: you can redistribute it and/or modify
00006 // it under the terms of the GNU General Public License as published by
00007 // the Free Software Foundation, either version 3 of the License, or
00008 // (at your option) any later version.
00009 //
00010 // This program is distributed in the hope that it will be useful,
00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013 // GNU General Public License for more details.
00014 //
00015 // You should have received a copy of the GNU General Public License
00016 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
00017 #ifndef __NOT_HH
00018 # define __NOT_HH
00019 
00020 # include "../strategies.hh"
00021 
00022 namespace aurelia {
00023 
00026   template <typename S>
00027   struct not_strategy {
00028   private: S s;
00029   public: not_strategy(const S& s): s(s) {}
00030     template <typename T>
00031     T operator()(const T& term) const {
00032       try {
00033         s(term);
00034       } catch (failure) {
00035         return term;
00036       }
00037       throw failure();
00038     }
00039   };
00040 
00045   template <typename S>
00046   not_strategy<S> not_(const S& s) {
00047     return not_strategy<S>(s);
00048   }
00049 
00050 }
00051 
00052 #endif