Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // static.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_STATIC_HPP_EAN_10_04_2005
Chris@16: #define BOOST_XPRESSIVE_DETAIL_STATIC_STATIC_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/mpl/assert.hpp>
Chris@16: #include <boost/xpressive/detail/detail_fwd.hpp>
Chris@16: #include <boost/xpressive/detail/core/state.hpp>
Chris@16: #include <boost/xpressive/detail/core/linker.hpp>
Chris@16: #include <boost/xpressive/detail/core/peeker.hpp>
Chris@16: #include <boost/xpressive/detail/static/placeholders.hpp>
Chris@16: #include <boost/xpressive/detail/utility/width.hpp>
Chris@16: 
Chris@16: // Random thoughts:
Chris@16: // - must support indirect repeat counts {$n,$m}
Chris@16: // - add ws to eat whitespace (make *ws illegal)
Chris@16: // - a{n,m}    -> repeat<n,m>(a)
Chris@16: // - a{$n,$m}  -> repeat(n,m)(a)
Chris@16: // - add nil to match nothing
Chris@16: // - instead of s1, s2, etc., how about s[1], s[2], etc.? Needlessly verbose?
Chris@16: 
Chris@16: namespace boost { namespace xpressive { namespace detail
Chris@16: {
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // stacked_xpression
Chris@16: //
Chris@16: template<typename Top, typename Next>
Chris@16: struct stacked_xpression
Chris@16:   : Next
Chris@16: {
Chris@16:     // match
Chris@16:     //  delegates to Next
Chris@16:     template<typename BidiIter>
Chris@16:     bool match(match_state<BidiIter> &state) const
Chris@16:     {
Chris@16:         return static_cast<Next const *>(this)->
Chris@16:             BOOST_NESTED_TEMPLATE push_match<Top>(state);
Chris@16:     }
Chris@16: 
Chris@16:     // top_match
Chris@16:     //   jump back to the xpression on top of the xpression stack,
Chris@16:     //   and keep the xpression on the stack.
Chris@16:     template<typename BidiIter>
Chris@16:     static bool top_match(match_state<BidiIter> &state, void const *top)
Chris@16:     {
Chris@16:         return static_cast<Top const *>(top)->
Chris@16:             BOOST_NESTED_TEMPLATE push_match<Top>(state);
Chris@16:     }
Chris@16: 
Chris@16:     // pop_match
Chris@16:     //   jump back to the xpression on top of the xpression stack,
Chris@16:     //   pop the xpression off the stack.
Chris@16:     template<typename BidiIter>
Chris@16:     static bool pop_match(match_state<BidiIter> &state, void const *top)
Chris@16:     {
Chris@16:         return static_cast<Top const *>(top)->match(state);
Chris@16:     }
Chris@16: 
Chris@16:     // skip_match
Chris@16:     //   pop the xpression off the top of the stack and ignore it; call
Chris@16:     //   match on next.
Chris@16:     template<typename BidiIter>
Chris@16:     bool skip_match(match_state<BidiIter> &state) const
Chris@16:     {
Chris@16:         // could be static_xpression::skip_impl or stacked_xpression::skip_impl
Chris@16:         // depending on if there is 1 or more than 1 xpression on the
Chris@16:         // xpression stack
Chris@16:         return Top::skip_impl(*static_cast<Next const *>(this), state);
Chris@16:     }
Chris@16: 
Chris@16: //protected:
Chris@16: 
Chris@16:     // skip_impl
Chris@16:     //   implementation of skip_match.
Chris@16:     template<typename That, typename BidiIter>
Chris@16:     static bool skip_impl(That const &that, match_state<BidiIter> &state)
Chris@16:     {
Chris@16:         return that.BOOST_NESTED_TEMPLATE push_match<Top>(state);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // stacked_xpression_cast
Chris@16: //
Chris@16: template<typename Top, typename Next>
Chris@16: inline stacked_xpression<Top, Next> const &stacked_xpression_cast(Next const &next)
Chris@16: {
Chris@16:     // NOTE: this is a little white lie. The "next" object doesn't really have
Chris@16:     // the type to which we're casting it. It is harmless, though. We are only using
Chris@16:     // the cast to decorate the next object with type information. It is done
Chris@16:     // this way to save stack space.
Chris@16:     BOOST_MPL_ASSERT_RELATION(sizeof(stacked_xpression<Top, Next>), ==, sizeof(Next));
Chris@16:     return *static_cast<stacked_xpression<Top, Next> const *>(&next);
Chris@16: }
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // static_xpression
Chris@16: //
Chris@16: template<typename Matcher, typename Next>
Chris@16: struct static_xpression
Chris@16:   : Matcher
Chris@16: {
Chris@16:     Next next_;
Chris@16: 
Chris@16:     BOOST_STATIC_CONSTANT(bool, pure = Matcher::pure && Next::pure);
Chris@16:     BOOST_STATIC_CONSTANT(
Chris@16:         std::size_t
Chris@16:       , width =
Chris@16:             Matcher::width != unknown_width::value && Next::width != unknown_width::value
Chris@16:           ? Matcher::width + Next::width
Chris@16:           : unknown_width::value
Chris@16:     );
Chris@16: 
Chris@16:     static_xpression(Matcher const &matcher = Matcher(), Next const &next = Next())
Chris@16:       : Matcher(matcher)
Chris@16:       , next_(next)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     // match
Chris@16:     //  delegates to the Matcher
Chris@16:     template<typename BidiIter>
Chris@16:     bool match(match_state<BidiIter> &state) const
Chris@16:     {
Chris@16:         return this->Matcher::match(state, this->next_);
Chris@16:     }
Chris@16: 
Chris@16:     // push_match
Chris@16:     //   call match on this, but also push "Top" onto the xpression
Chris@16:     //   stack so we know what we are jumping back to later.
Chris@16:     template<typename Top, typename BidiIter>
Chris@16:     bool push_match(match_state<BidiIter> &state) const
Chris@16:     {
Chris@16:         return this->Matcher::match(state, stacked_xpression_cast<Top>(this->next_));
Chris@16:     }
Chris@16: 
Chris@16:     // skip_impl
Chris@16:     //   implementation of skip_match, called from stacked_xpression::skip_match
Chris@16:     template<typename That, typename BidiIter>
Chris@16:     static bool skip_impl(That const &that, match_state<BidiIter> &state)
Chris@16:     {
Chris@16:         return that.match(state);
Chris@16:     }
Chris@16: 
Chris@16:     // for linking a compiled regular xpression
Chris@16:     template<typename Char>
Chris@16:     void link(xpression_linker<Char> &linker) const
Chris@16:     {
Chris@16:         linker.accept(*static_cast<Matcher const *>(this), &this->next_);
Chris@16:         this->next_.link(linker);
Chris@16:     }
Chris@16: 
Chris@16:     // for building a lead-follow
Chris@16:     template<typename Char>
Chris@16:     void peek(xpression_peeker<Char> &peeker) const
Chris@16:     {
Chris@16:         this->peek_next_(peeker.accept(*static_cast<Matcher const *>(this)), peeker);
Chris@16:     }
Chris@16: 
Chris@16:     // for getting xpression width
Chris@16:     detail::width get_width() const
Chris@16:     {
Chris@16:         return this->get_width_(mpl::size_t<width>());
Chris@16:     }
Chris@16: 
Chris@16: private:
Chris@16: 
Chris@16:     static_xpression &operator =(static_xpression const &);
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     void peek_next_(mpl::true_, xpression_peeker<Char> &peeker) const
Chris@16:     {
Chris@16:         this->next_.peek(peeker);
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     void peek_next_(mpl::false_, xpression_peeker<Char> &) const
Chris@16:     {
Chris@16:         // no-op
Chris@16:     }
Chris@16: 
Chris@16:     template<std::size_t Width>
Chris@16:     detail::width get_width_(mpl::size_t<Width>) const
Chris@16:     {
Chris@16:         return Width;
Chris@16:     }
Chris@16: 
Chris@16:     detail::width get_width_(unknown_width) const
Chris@16:     {
Chris@16:         // Should only be called in contexts where the width is
Chris@16:         // known to be fixed.
Chris@16:         return this->Matcher::get_width() + this->next_.get_width();
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // make_static
Chris@16: //
Chris@16: template<typename Matcher>
Chris@16: inline static_xpression<Matcher> const
Chris@16: make_static(Matcher const &matcher)
Chris@16: {
Chris@16:     return static_xpression<Matcher>(matcher);
Chris@16: }
Chris@16: 
Chris@16: template<typename Matcher, typename Next>
Chris@16: inline static_xpression<Matcher, Next> const
Chris@16: make_static(Matcher const &matcher, Next const &next)
Chris@16: {
Chris@16:     return static_xpression<Matcher, Next>(matcher, next);
Chris@16: }
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // no_next
Chris@16: //
Chris@16: struct no_next
Chris@16: {
Chris@16:     BOOST_STATIC_CONSTANT(std::size_t, width = 0);
Chris@16:     BOOST_STATIC_CONSTANT(bool, pure = true);
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     void link(xpression_linker<Char> &) const
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     template<typename Char>
Chris@16:     void peek(xpression_peeker<Char> &peeker) const
Chris@16:     {
Chris@16:         peeker.fail();
Chris@16:     }
Chris@16: 
Chris@16:     detail::width get_width() const
Chris@16:     {
Chris@16:         return 0;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // get_mark_number
Chris@16: //
Chris@16: inline int get_mark_number(basic_mark_tag const &mark)
Chris@16: {
Chris@16:     return proto::value(mark).mark_number_;
Chris@16: }
Chris@16: 
Chris@16: }}} // namespace boost::xpressive::detail
Chris@16: 
Chris@16: #endif