| // Copyright (c) 2001 Daniel C. Nuffer |
| // Copyright (c) 2001-2010 Hartmut Kaiser |
| // |
| // 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) |
| |
| #if !defined(BOOST_SPIRIT_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM) |
| #define BOOST_SPIRIT_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM |
| |
| #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp> |
| #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp> |
| |
| namespace boost { namespace spirit { namespace iterator_policies |
| { |
| /////////////////////////////////////////////////////////////////////////////// |
| // class lex_input |
| // Implementation of the InputPolicy used by multi_pass |
| // |
| // The lex_input class gets tokens (integers) from yylex() |
| /////////////////////////////////////////////////////////////////////////// |
| struct lex_input |
| { |
| typedef int value_type; |
| |
| /////////////////////////////////////////////////////////////////////// |
| template <typename T> |
| class unique : public detail::default_input_policy |
| { |
| public: |
| typedef std::ptrdiff_t difference_type; |
| typedef std::ptrdiff_t distance_type; |
| typedef int* pointer; |
| typedef int& reference; |
| |
| protected: |
| unique() {} |
| explicit unique(T) {} |
| |
| public: |
| template <typename MultiPass> |
| static typename MultiPass::reference get_input(MultiPass& mp) |
| { |
| value_type& curtok = mp.shared()->curtok; |
| if (-1 == curtok) |
| { |
| extern int yylex(); |
| curtok = yylex(); |
| } |
| return curtok; |
| } |
| |
| template <typename MultiPass> |
| static void advance_input(MultiPass& mp) |
| { |
| extern int yylex(); |
| mp.shared()->curtok = yylex(); |
| } |
| |
| // test, whether we reached the end of the underlying stream |
| template <typename MultiPass> |
| static bool input_at_eof(MultiPass const& mp) |
| { |
| return mp.shared()->curtok == 0; |
| } |
| |
| template <typename MultiPass> |
| static bool input_is_valid(MultiPass const&, value_type const& t) |
| { |
| return -1 != t; |
| } |
| }; |
| |
| /////////////////////////////////////////////////////////////////////// |
| template <typename T> |
| struct shared |
| { |
| explicit shared(T) : curtok(-1) {} |
| |
| value_type curtok; |
| }; |
| }; |
| |
| }}} |
| |
| #endif |
| |