1 // Boost.Units - A C++ library for zero-overhead dimensional analysis and 2 // unit/quantity manipulation and conversion 3 // 4 // Copyright (C) 2003-2008 Matthias Christian Schabel 5 // Copyright (C) 2007-2008 Steven Watanabe 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See 8 // accompanying file LICENSE_1_0.txt or copy at 9 // http://www.boost.org/LICENSE_1_0.txt) 10 11 #ifndef BOOST_UNITS_DIMENSIONLESS_TYPE_HPP 12 #define BOOST_UNITS_DIMENSIONLESS_TYPE_HPP 13 14 /// 15 /// \file 16 /// \brief Dimension lists in which all exponents resolve to zero reduce to @c dimensionless_type. 17 /// 18 19 #include <boost/mpl/long.hpp> 20 #include <boost/mpl/deref.hpp> 21 #include <boost/mpl/arithmetic.hpp> 22 23 #include <boost/units/config.hpp> 24 25 namespace boost { 26 27 namespace units { 28 29 namespace detail { 30 31 struct dimension_list_tag; 32 33 } 34 35 /// Dimension lists in which all exponents resolve to zero reduce to @c dimensionless_type. 36 struct dimensionless_type 37 { 38 typedef dimensionless_type type; 39 typedef detail::dimension_list_tag tag; 40 typedef mpl::long_<0> size; 41 }; 42 43 } // namespace units 44 45 } // namespace boost 46 47 #if BOOST_UNITS_HAS_BOOST_TYPEOF 48 49 #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() 50 51 BOOST_TYPEOF_REGISTER_TYPE(boost::units::dimensionless_type) 52 53 #endif 54 55 #endif // BOOST_UNITS_DIMENSIONLESS_TYPE_HPP 56