Vaucanson 1.4
monoid_base.hxx
00001 // monoid_base.hxx: this file is part of the Vaucanson project.
00002 //
00003 // Vaucanson, a generic library for finite state machines.
00004 //
00005 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2010 The Vaucanson Group.
00006 //
00007 // This program is free software; you can redistribute it and/or
00008 // modify it under the terms of the GNU General Public License
00009 // as published by the Free Software Foundation; either version 2
00010 // of the License, or (at your option) any later version.
00011 //
00012 // The complete GNU General Public Licence Notice can be found as the
00013 // `COPYING' file in the root directory.
00014 //
00015 // The Vaucanson Group consists of people listed in the `AUTHORS' file.
00016 //
00017 #ifndef VCSN_ALGEBRA_CONCEPT_MONOID_BASE_HXX
00018 # define VCSN_ALGEBRA_CONCEPT_MONOID_BASE_HXX
00019 
00020 # include <vaucanson/algebra/concept/monoid_base.hh>
00021 # include <vaucanson/algebra/concept/semigroup_base.hh>
00022 
00023 namespace vcsn {
00024 
00025   namespace algebra {
00026 
00027     /*-----------------.
00028     | MonoidBase<Self> |
00029     `-----------------*/
00030     template<class Self>
00031     template<typename T>
00032     Element<Self, T>
00033     MonoidBase<Self>::identity(SELECTOR(T)) const
00034     {
00035       return Element<Self, T>(this->self(),
00036                               identity_value(SELECT(Self), SELECT(T)));
00037     }
00038 
00039     template<class Self>
00040     template<typename T>
00041     Element<Self, T>  MonoidBase<Self>::zero(SELECTOR(T)) const
00042     {
00043       return Element<Self, T>(this->self(),
00044                               zero_value(SELECT(Self), SELECT(T)));
00045     }
00046 
00047     template <class Self>
00048     MonoidBase<Self>::MonoidBase()
00049     {}
00050 
00051     template <class Self>
00052     MonoidBase<Self>::MonoidBase(const MonoidBase& other) :
00053       SemigroupBase<Self>(other)
00054     {}
00055 
00056     template <class T>
00057     template <class S>
00058     Element<S, T>
00059     identity_as<T>::of(const S& s)
00060     {
00061       return s.identity(SELECT(T));
00062     }
00063 
00064     template <class T>
00065     template <class S>
00066     Element<S, T>
00067     zero_as<T>::of(const S& s)
00068     {
00069       return s.zero(SELECT(T));
00070     }
00071 
00072   } // algebra
00073 
00074     /*---------------------------------.
00075     | MetaElement<MonoidBase<Self>, T> |
00076     `---------------------------------*/
00077 
00078   template<class Self, typename T>
00079   MetaElement<algebra::MonoidBase<Self>, T>::MetaElement()
00080   {}
00081 
00082   template<class Self, typename T>
00083   MetaElement<algebra::MonoidBase<Self>, T>::MetaElement(const MetaElement& other) :
00084     MetaElement<algebra::SemigroupBase<Self>, T>(other)
00085   {}
00086 
00087   namespace algebra {
00088 
00089     template<typename T, typename Self>
00090     T
00091     op_default(SELECTOR(algebra::MonoidBase<Self>), SELECTOR(T))
00092     {
00093       // By default, an element of a monoid is the identity.
00094       return identity_value(SELECT(Self), SELECT(T));
00095     }
00096 
00097   } // algebra
00098 
00099 } // vcsn
00100 
00101 #endif // ! VCSN_ALGEBRA_CONCEPT_MONOID_BASE_HXX