| /////////////////////////////////////////////////////////////////////////////// |
| // optional_matcher.hpp |
| // |
| // Copyright 2008 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_CORE_MATCHER_OPTIONAL_MATCHER_HPP_EAN_10_04_2005 |
| #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_OPTIONAL_MATCHER_HPP_EAN_10_04_2005 |
| |
| // MS compatible compilers support #pragma once |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| # pragma once |
| #endif |
| |
| #include <boost/mpl/bool.hpp> |
| #include <boost/xpressive/detail/detail_fwd.hpp> |
| #include <boost/xpressive/detail/core/quant_style.hpp> |
| #include <boost/xpressive/detail/core/state.hpp> |
| |
| namespace boost { namespace xpressive { namespace detail |
| { |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // optional_matcher |
| template<typename Xpr, typename Greedy> |
| struct optional_matcher |
| : quant_style<quant_variable_width, unknown_width::value, Xpr::pure> |
| { |
| Xpr xpr_; |
| |
| explicit optional_matcher(Xpr const &xpr) |
| : xpr_(xpr) |
| { |
| } |
| |
| template<typename BidiIter, typename Next> |
| bool match(match_state<BidiIter> &state, Next const &next) const |
| { |
| return this->match_(state, next, Greedy()); |
| } |
| |
| private: |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const // Greedy |
| { |
| return this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state) |
| || next.match(state); |
| } |
| |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const // Non-greedy |
| { |
| return next.match(state) |
| || this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state); |
| } |
| |
| optional_matcher &operator =(optional_matcher const &); |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // optional_mark_matcher |
| template<typename BidiIter, typename Next> |
| inline bool match_next(match_state<BidiIter> &state, Next const &next, int mark_number) |
| { |
| sub_match_impl<BidiIter> &br = state.sub_match(mark_number); |
| |
| bool old_matched = br.matched; |
| br.matched = false; |
| |
| if(next.match(state)) |
| { |
| return true; |
| } |
| |
| br.matched = old_matched; |
| return false; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // optional_mark_matcher |
| template<typename Xpr, typename Greedy> |
| struct optional_mark_matcher |
| : quant_style<quant_variable_width, unknown_width::value, Xpr::pure> |
| { |
| Xpr xpr_; |
| int mark_number_; |
| |
| explicit optional_mark_matcher(Xpr const &xpr, int mark_number) |
| : xpr_(xpr) |
| , mark_number_(mark_number) |
| { |
| } |
| |
| template<typename BidiIter, typename Next> |
| bool match(match_state<BidiIter> &state, Next const &next) const |
| { |
| return this->match_(state, next, Greedy()); |
| } |
| |
| private: |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const // Greedy |
| { |
| return this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state) |
| || match_next(state, next, this->mark_number_); |
| } |
| |
| template<typename BidiIter, typename Next> |
| bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const // Non-greedy |
| { |
| return match_next(state, next, this->mark_number_) |
| || this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state); |
| } |
| |
| optional_mark_matcher &operator =(optional_mark_matcher const &); |
| }; |
| |
| }}} |
| |
| #endif |