1 ///////////////////////////////////////////////////////////////////////////////
2 // attr_begin_matcher.hpp
3 //
4 //  Copyright 2008 Eric Niebler. Distributed under the Boost
5 //  Software License, Version 1.0. (See accompanying file
6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 
8 #ifndef BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_ATTR_BEGIN_MATCHER_HPP_EAN_06_09_2007
9 #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_ATTR_BEGIN_MATCHER_HPP_EAN_06_09_2007
10 
11 // MS compatible compilers support #pragma once
12 #if defined(_MSC_VER)
13 # pragma once
14 #endif
15 
16 #include <boost/xpressive/detail/detail_fwd.hpp>
17 #include <boost/xpressive/detail/core/quant_style.hpp>
18 #include <boost/xpressive/detail/core/state.hpp>
19 
20 namespace boost { namespace xpressive { namespace detail
21 {
22 
23     ///////////////////////////////////////////////////////////////////////////////
24     // attr_begin_matcher
25     //
26     template<typename Nbr>
27     struct attr_begin_matcher
28       : quant_style<quant_none, 0, false>
29     {
30         template<typename BidiIter, typename Next>
matchboost::xpressive::detail::attr_begin_matcher31         static bool match(match_state<BidiIter> &state, Next const &next)
32         {
33             void const *attr_slots[Nbr::value] = {};
34             attr_context old_attr_context = state.attr_context_;
35             state.attr_context_.attr_slots_ = attr_slots;
36             state.attr_context_.prev_attr_context_ = &old_attr_context;
37 
38             if(next.match(state))
39             {
40                 return true;
41             }
42 
43             state.attr_context_ = old_attr_context;
44             return false;
45         }
46     };
47 
48 }}}
49 
50 #endif
51