/////////////////////////////////////////////////////////////////////////////// | |
// 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 |