boost/icl/type_traits/unit_element.hpp
/*-----------------------------------------------------------------------------+
Copyright (c) 2008-2010: Joachim Faulhaber
+------------------------------------------------------------------------------+
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENCE.txt or copy at
http://www.boost.org/LICENSE_1_0.txt)
+-----------------------------------------------------------------------------*/
#ifndef BOOST_ICL_TYPE_TRAITS_UNIT_ELEMENT_HPP_JOFA_080912
#define BOOST_ICL_TYPE_TRAITS_UNIT_ELEMENT_HPP_JOFA_080912
#include <string>
#include <boost/icl/type_traits/identity_element.hpp>
#include <boost/icl/type_traits/succ_pred.hpp>
namespace boost{ namespace icl
{
template <class Type> struct unit_element{ static Type value(); };
template<> inline bool unit_element<bool>::value() { return true;}
template<> inline float unit_element<float>::value() { return 1.0; }
template<> inline double unit_element<double>::value() { return 1.0; }
template<> inline long double unit_element<long double>::value()
{ return 1.0; }
// Smallest 'visible' string that is greater than the empty string.
template <>
inline std::string unit_element<std::string>::value()
{ return std::string(" "); }
template <class Type>
inline Type unit_element<Type>::value()
{ return icl::succ(identity_element<Type>::value()); }
}} // namespace boost icl
#endif