boost/xpressive/detail/static/width_of.hpp
/////////////////////////////////////////////////////////////////////////////// // width_of.hpp // // Copyright 2007 Eric Niebler. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) #ifndef BOOST_XPRESSIVE_DETAIL_STATIC_WIDTH_OF_HPP_EAN_10_04_2005 #define BOOST_XPRESSIVE_DETAIL_STATIC_WIDTH_OF_HPP_EAN_10_04_2005 // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif #include <boost/ref.hpp> #include <boost/mpl/if.hpp> #include <boost/mpl/or.hpp> #include <boost/mpl/plus.hpp> #include <boost/mpl/times.hpp> #include <boost/mpl/assert.hpp> #include <boost/mpl/size_t.hpp> #include <boost/mpl/equal_to.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/xpressive/detail/detail_fwd.hpp> #include <boost/xpressive/proto/traits.hpp> namespace boost { namespace xpressive { namespace detail { /////////////////////////////////////////////////////////////////////////////// // is_char // template<typename T> struct is_char : mpl::false_ {}; template<> struct is_char<char> : mpl::true_ {}; template<> struct is_char<wchar_t> : mpl::true_ {}; /////////////////////////////////////////////////////////////////////////////// // width_of_terminal // template<typename Expr, typename Char, bool IsXpr = is_xpr<Expr>::value> struct width_of_terminal : mpl::size_t<Expr::width> // xpressive literals {}; template<typename Expr, typename Char> struct width_of_terminal<Expr, Char, false> : unknown_width // unknown literals (eg, basic_string, basic_regex, etc.) {}; template<typename Char> struct width_of_terminal<Char, Char, false> : mpl::size_t<1> // char literals {}; template<typename Char> struct width_of_terminal<char, Char, false> : mpl::size_t<1> // char literals {}; template<> struct width_of_terminal<char, char, false> : mpl::size_t<1> // char literals {}; template<typename Elem, std::size_t N, typename Char> struct width_of_terminal<Elem (&) [N], Char, false> : mpl::size_t<N-is_char<Elem>::value> // string literals {}; template<typename Elem, std::size_t N, typename Char> struct width_of_terminal<Elem const (&) [N], Char, false> : mpl::size_t<N-is_char<Elem>::value> // string literals {}; /////////////////////////////////////////////////////////////////////////////// // width_of // template<typename Expr, typename Char, typename Tag = typename Expr::proto_tag> struct width_of {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::terminal> : width_of_terminal<typename proto::result_of::arg<Expr>::type, Char> {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::shift_right> : mpl::if_< mpl::or_< mpl::equal_to<unknown_width, width_of<typename Expr::proto_arg0::proto_base_expr, Char> > , mpl::equal_to<unknown_width, width_of<typename Expr::proto_arg1::proto_base_expr, Char> > > , unknown_width , mpl::plus< width_of<typename Expr::proto_arg0::proto_base_expr, Char> , width_of<typename Expr::proto_arg1::proto_base_expr, Char> > >::type {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::bitwise_or> : mpl::if_< mpl::or_< mpl::equal_to<unknown_width, width_of<typename Expr::proto_arg0::proto_base_expr, Char> > , mpl::not_equal_to< width_of<typename Expr::proto_arg0::proto_base_expr, Char> , width_of<typename Expr::proto_arg1::proto_base_expr, Char> > > , unknown_width , width_of<typename Expr::proto_arg0::proto_base_expr, Char> >::type {}; template<typename Expr, typename Char, typename Left> struct width_of_assign {}; template<typename Expr, typename Char> struct width_of_assign<Expr, Char, mark_placeholder> : width_of<typename Expr::proto_arg1::proto_base_expr, Char> {}; template<typename Expr, typename Char> struct width_of_assign<Expr, Char, set_initializer> : mpl::size_t<1> {}; template<typename Expr, typename Char, typename Nbr> struct width_of_assign<Expr, Char, attribute_placeholder<Nbr> > : unknown_width {}; // either (s1 = ...) or (a1 = ...) or (set = ...) template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::assign> : width_of_assign<Expr, Char, typename proto::result_of::arg<typename Expr::proto_arg0>::type> {}; template<typename Expr, typename Char> struct width_of<Expr, Char, modifier_tag> : width_of<typename Expr::proto_arg1::proto_base_expr, Char> {}; template<typename Expr, typename Char> struct width_of<Expr, Char, lookahead_tag> : mpl::size_t<0> {}; template<typename Expr, typename Char> struct width_of<Expr, Char, lookbehind_tag> : mpl::size_t<0> {}; // keep() is used to turn off backtracking, so they should only be used // for things that are variable-width (eg. quantified) template<typename Expr, typename Char> struct width_of<Expr, Char, keeper_tag> : unknown_width { // If this assert fires, you put something that doesn't require backtracking // in a keep(). In that case, the keep() is not necessary and you should just // remove it. BOOST_MPL_ASSERT_RELATION((width_of<typename Expr::proto_arg0::proto_base_expr, Char>::value), ==, unknown_width::value); }; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::posit> : unknown_width {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::dereference> : unknown_width {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::logical_not> : unknown_width {}; template<typename Expr, typename Char, uint_t Min, uint_t Max> struct width_of<Expr, Char, generic_quant_tag<Min, Max> > : unknown_width {}; template<typename Expr, typename Char, uint_t Count> struct width_of<Expr, Char, generic_quant_tag<Count, Count> > : mpl::if_< mpl::equal_to<unknown_width, width_of<typename Expr::proto_arg0::proto_base_expr, Char> > , unknown_width , mpl::times< width_of<typename Expr::proto_arg0::proto_base_expr, Char> , mpl::size_t<Count> > >::type {}; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::negate> : width_of<typename Expr::proto_arg0::proto_base_expr, Char> {}; // when complementing a set or an assertion, the width is that of the set (1) or the assertion (0) template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::complement> : width_of<typename Expr::proto_arg0::proto_base_expr, Char> {}; // The comma is used in list-initialized sets, and the width of sets are 1 template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::comma> : mpl::size_t<1> {}; // The subscript operator[] is used for sets, as in set['a' | range('b','h')], // or for actions as in (any >> expr)[ action ] template<typename Expr, typename Char, typename Left> struct width_of_subscript : width_of<Left, Char> {}; template<typename Expr, typename Char> struct width_of_subscript<Expr, Char, set_initializer_type> : mpl::size_t<1> { // If Left is "set" then make sure that Right has a width_of 1 BOOST_MPL_ASSERT_RELATION(1, ==, (width_of<typename Expr::proto_arg1::proto_base_expr, Char>::value)); }; template<typename Expr, typename Char> struct width_of<Expr, Char, proto::tag::subscript> : width_of_subscript<Expr, Char, typename Expr::proto_arg0::proto_base_expr> {}; }}} // namespace boost::xpressive::detail #endif