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///////////////////////////////////////////////////////////////////////////////
// flow_control.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_FLOW_CONTROL_HPP_EAN_10_04_2005
#define BOOST_XPRESSIVE_DETAIL_CORE_FLOW_CONTROL_HPP_EAN_10_04_2005
// MS compatible compilers support #pragma once
#if defined(_MSC_VER)
# pragma once
#endif
#include <boost/xpressive/detail/detail_fwd.hpp>
#include <boost/xpressive/detail/core/regex_impl.hpp>
#include <boost/xpressive/detail/core/state.hpp>
#include <boost/xpressive/detail/utility/ignore_unused.hpp>
namespace boost { namespace xpressive { namespace detail
{
///////////////////////////////////////////////////////////////////////////////
// push_context_match
//
template<typename BidiIter>
inline bool push_context_match
(
regex_impl<BidiIter> const &impl
, match_state<BidiIter> &state
, matchable<BidiIter> const &next
)
{
// avoid infinite recursion
// BUGBUG this only catches direct infinite recursion, like sregex::compile("(?R)"), but
// not indirect infinite recursion where two rules invoke each other recursively.
if(state.is_active_regex(impl) && state.cur_ == state.sub_match(0).begin_)
{
return next.match(state);
}
// save state
match_context<BidiIter> context = state.push_context(impl, next, context);
detail::ignore_unused(context);
// match the nested regex and uninitialize the match context
// (reclaims the sub_match objects if necessary)
return state.pop_context(impl, impl.xpr_->match(state));
}
///////////////////////////////////////////////////////////////////////////////
// pop_context_match
//
template<typename BidiIter>
inline bool pop_context_match(match_state<BidiIter> &state)
{
// save state
// BUGBUG nested regex could have changed state.traits_
match_context<BidiIter> &context(*state.context_.prev_context_);
state.swap_context(context);
// Finished matching the nested regex; now match the rest of the enclosing regex
bool success = context.next_ptr_->match(state);
// restore state
state.swap_context(context);
return success;
}
}}} // namespace boost::xpressive::detail
#endif