Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // width_of.hpp
Chris@16: //
Chris@16: //  Copyright 2008 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_XPRESSIVE_DETAIL_STATIC_WIDTH_OF_HPP_EAN_10_04_2005
Chris@16: #define BOOST_XPRESSIVE_DETAIL_STATIC_WIDTH_OF_HPP_EAN_10_04_2005
Chris@16: 
Chris@16: // MS compatible compilers support #pragma once
Chris@101: #if defined(_MSC_VER)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/ref.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/or.hpp>
Chris@16: #include <boost/mpl/plus.hpp>
Chris@16: #include <boost/mpl/times.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/mpl/size_t.hpp>
Chris@16: #include <boost/mpl/equal_to.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: #include <boost/xpressive/detail/detail_fwd.hpp>
Chris@16: #include <boost/xpressive/detail/static/type_traits.hpp>
Chris@16: #include <boost/proto/traits.hpp>
Chris@16: 
Chris@16: namespace boost { namespace xpressive { namespace detail
Chris@16: {
Chris@16:     template<typename Expr, typename Char, typename Tag = typename Expr::proto_tag>
Chris@16:     struct width_of;
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // add_widths
Chris@16:     //
Chris@16:     template<std::size_t N, std::size_t M>
Chris@16:     struct add_widths
Chris@16:       : mpl::size_t<N + M>
Chris@16:     {};
Chris@16: 
Chris@16:     template<std::size_t M>
Chris@16:     struct add_widths<unknown_width::value, M>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<std::size_t N>
Chris@16:     struct add_widths<N, unknown_width::value>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<>
Chris@16:     struct add_widths<unknown_width::value, unknown_width::value>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // or_widths
Chris@16:     //
Chris@16:     template<std::size_t N, std::size_t M>
Chris@16:     struct or_widths
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<std::size_t N>
Chris@16:     struct or_widths<N, N>
Chris@16:       : mpl::size_t<N>
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // width_of_terminal
Chris@16:     //
Chris@16:     template<typename Expr, typename Char, bool IsXpr = is_xpr<Expr>::value>
Chris@16:     struct width_of_terminal
Chris@16:       : mpl::size_t<Expr::width>    // xpressive literals
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of_terminal<Expr, Char, false>
Chris@16:       : unknown_width       // unknown literals (eg, basic_string, basic_regex, etc.)
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     struct width_of_terminal<Char, Char, false>
Chris@16:       : mpl::size_t<1>      // char literals
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     struct width_of_terminal<char, Char, false>
Chris@16:       : mpl::size_t<1>      // char literals
Chris@16:     {};
Chris@16: 
Chris@16:     template<>
Chris@16:     struct width_of_terminal<char, char, false>
Chris@16:       : mpl::size_t<1>      // char literals
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Elem, std::size_t N, typename Char>
Chris@16:     struct width_of_terminal<Elem (&) [N], Char, false>
Chris@16:       : mpl::size_t<N-is_char<Elem>::value>    // string literals
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Elem, std::size_t N, typename Char>
Chris@16:     struct width_of_terminal<Elem const (&) [N], Char, false>
Chris@16:       : mpl::size_t<N-is_char<Elem>::value>    // string literals
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // width_of
Chris@16:     //
Chris@16:     template<typename Expr, typename Char, typename Tag>
Chris@16:     struct width_of
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::terminal>
Chris@16:       : width_of_terminal<typename proto::result_of::value<Expr>::type, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::shift_right>
Chris@16:       : add_widths<
Chris@16:             width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>::value
Chris@16:           , width_of<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>::value
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::bitwise_or>
Chris@16:       : or_widths<
Chris@16:             width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>::value
Chris@16:           , width_of<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>::value
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, typename Left>
Chris@16:     struct width_of_assign
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of_assign<Expr, Char, mark_placeholder>
Chris@16:       : width_of<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of_assign<Expr, Char, set_initializer>
Chris@16:       : mpl::size_t<1>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, typename Nbr>
Chris@16:     struct width_of_assign<Expr, Char, attribute_placeholder<Nbr> >
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     // either (s1 = ...) or (a1 = ...) or (set = ...)
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::assign>
Chris@16:       : width_of_assign<
Chris@16:             Expr
Chris@16:           , Char
Chris@16:           , typename proto::result_of::value<
Chris@16:                 typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr
Chris@16:             >::type
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, modifier_tag>
Chris@16:       : width_of<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, lookahead_tag>
Chris@16:       : mpl::size_t<0>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, lookbehind_tag>
Chris@16:       : mpl::size_t<0>
Chris@16:     {};
Chris@16: 
Chris@16:     // keep() is used to turn off backtracking, so they should only be used
Chris@16:     // for things that are variable-width (eg. quantified)
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, keeper_tag>
Chris@16:       : unknown_width
Chris@16:     {
Chris@16:         // TODO: keep() now has a second meaning: execute actions immediately.
Chris@16:         // In that sense, it is perfectly reasonable to put a fixed-width
Chris@16:         // sub-expression in a keep. Can fixed-width keep() sub-expressions
Chris@16:         // use the simple_repeat_matcher?
Chris@16:     };
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::unary_plus>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::dereference>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::logical_not>
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, uint_t Min, uint_t Max>
Chris@16:     struct width_of<Expr, Char, generic_quant_tag<Min, Max> >
Chris@16:       : unknown_width
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, uint_t Count>
Chris@16:     struct width_of<Expr, Char, generic_quant_tag<Count, Count> >
Chris@16:       : mpl::if_c<
Chris@16:             mpl::equal_to<unknown_width, width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> >::value
Chris@16:           , unknown_width
Chris@16:           , mpl::times<
Chris@16:                 width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:               , mpl::size_t<Count>
Chris@16:             >
Chris@16:         >::type
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::negate>
Chris@16:       : width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     // when complementing a set or an assertion, the width is that of the set (1) or the assertion (0)
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::complement>
Chris@16:       : width_of<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     // The comma is used in list-initialized sets, and the width of sets are 1
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::comma>
Chris@16:       : mpl::size_t<1>
Chris@16:     {};
Chris@16: 
Chris@16:     // The subscript operator[] is used for sets, as in set['a' | range('b','h')],
Chris@16:     // or for actions as in (any >> expr)[ action ]
Chris@16:     template<typename Expr, typename Char, typename Left>
Chris@16:     struct width_of_subscript
Chris@16:       : width_of<Left, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of_subscript<Expr, Char, set_initializer_type>
Chris@16:       : mpl::size_t<1>
Chris@16:     {
Chris@16:         // If Left is "set" then make sure that Right has a width_of 1
Chris@16:         BOOST_MPL_ASSERT_RELATION(
Chris@16:             1
Chris@16:           , ==
Chris@16:           , (width_of<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>::value));
Chris@16:     };
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct width_of<Expr, Char, proto::tag::subscript>
Chris@16:       : width_of_subscript<Expr, Char, typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr>
Chris@16:     {};
Chris@16: 
Chris@16: }}} // namespace boost::xpressive::detail
Chris@16: 
Chris@16: #undef UNREF
Chris@16: 
Chris@16: #endif