1 #ifndef BOOST_METAPARSE_V1_ONE_CHAR_HPP 2 #define BOOST_METAPARSE_V1_ONE_CHAR_HPP 3 4 // Copyright Abel Sinkovics (abel@sinkovics.hu) 2009 - 2011. 5 // Distributed under the Boost Software License, Version 1.0. 6 // (See accompanying file LICENSE_1_0.txt or copy at 7 // http://www.boost.org/LICENSE_1_0.txt) 8 9 #include <boost/metaparse/v1/error/unexpected_end_of_input.hpp> 10 #include <boost/metaparse/v1/next_char.hpp> 11 #include <boost/metaparse/v1/next_line.hpp> 12 #include <boost/metaparse/v1/accept.hpp> 13 #include <boost/metaparse/v1/reject.hpp> 14 #include <boost/metaparse/v1/get_prev_char.hpp> 15 16 #include <boost/mpl/empty.hpp> 17 #include <boost/mpl/eval_if.hpp> 18 #include <boost/mpl/front.hpp> 19 #include <boost/mpl/pop_front.hpp> 20 #include <boost/mpl/bool.hpp> 21 22 namespace boost 23 { 24 namespace metaparse 25 { 26 namespace v1 27 { 28 struct one_char 29 { 30 private: 31 template <class C, class Pos> 32 struct next_pos : 33 boost::mpl::eval_if< 34 boost::mpl::bool_< 35 C::type::value == '\r' 36 || ( 37 C::type::value == '\n' 38 && get_prev_char<Pos>::type::value != '\r' 39 ) 40 >, 41 next_line<Pos, C>, 42 next_char<Pos, C> 43 > 44 {}; 45 46 template <class S, class NextPos> 47 struct unchecked : 48 accept< 49 typename boost::mpl::front<S>::type, 50 boost::mpl::pop_front<S>, 51 NextPos 52 > 53 {}; 54 public: 55 typedef one_char type; 56 57 template <class S, class Pos> 58 struct apply : 59 boost::mpl::eval_if< 60 typename boost::mpl::empty<S>::type, 61 reject<error::unexpected_end_of_input, Pos>, 62 unchecked<S, next_pos<boost::mpl::front<S>, Pos> > 63 > 64 {}; 65 }; 66 } 67 } 68 } 69 70 #endif 71 72