text: /*=============================================================================
      Copyright (c) 2001-2011 Hartmut Kaiser
      Copyright (c) 2011      Bryce Lelbach
  
      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(SPIRIT_QI_BOOL_SEP_29_2009_0709AM)
  #define SPIRIT_QI_BOOL_SEP_29_2009_0709AM
  
  #if defined(_MSC_VER)
  #pragma once
  #endif
  
  #include <boost/spirit/home/qi/skip_over.hpp>
  #include <boost/spirit/home/qi/detail/enable_lit.hpp>
  #include <boost/spirit/home/qi/meta_compiler.hpp>
  #include <boost/spirit/home/qi/parser.hpp>
  #include <boost/spirit/home/qi/numeric/bool_policies.hpp>
  #include <boost/spirit/home/support/common_terminals.hpp>
  #include <boost/mpl/assert.hpp>
  #include <boost/detail/workaround.hpp>
  #include <boost/type_traits/is_same.hpp>
  
  namespace boost { namespace spirit
  {
      namespace qi
      {
          ///////////////////////////////////////////////////////////////////////
          // forward declaration only
          template <typename T>
          struct bool_policies;
  
          ///////////////////////////////////////////////////////////////////////
          // This is the class that the user can instantiate directly in
          // order to create a customized bool parser
          template <typename T, typename BoolPolicies = bool_policies<T> >
          struct bool_parser
            : spirit::terminal<tag::stateful_tag<BoolPolicies, tag::bool_, T> >
          {
              typedef tag::stateful_tag<BoolPolicies, tag::bool_, T> tag_type;
  
              bool_parser() {}
              bool_parser(BoolPolicies const& data)
                : spirit::terminal<tag_type>(data) {}
          };
      }
  
      ///////////////////////////////////////////////////////////////////////////
      // Enablers
      ///////////////////////////////////////////////////////////////////////////
      template <> // enables bool_
      struct use_terminal<qi::domain, tag::bool_>
        : mpl::true_ {};
  
      template <> // enables true_
      struct use_terminal<qi::domain, tag::true_>
        : mpl::true_ {};
  
      template <> // enables false_
      struct use_terminal<qi::domain, tag::false_>
        : mpl::true_ {};
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename A0> // enables lit(...)
      struct use_terminal<qi::domain
          , terminal_ex<tag::lit, fusion::vector1<A0> >
          , typename enable_if<is_same<A0, bool> >::type>
        : mpl::true_ {};
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename A0> // enables bool_(...)
      struct use_terminal<qi::domain
        , terminal_ex<tag::bool_, fusion::vector1<A0> >
      > : mpl::true_ {};
  
      template <> // enables *lazy* bool_(...)
      struct use_lazy_terminal<qi::domain, tag::bool_, 1>
        : mpl::true_ {};
  
      ///////////////////////////////////////////////////////////////////////////
      // enables any custom bool_parser
      template <typename T, typename BoolPolicies>
      struct use_terminal<qi::domain
          , tag::stateful_tag<BoolPolicies, tag::bool_, T> >
        : mpl::true_ {};
  
      // enables any custom bool_parser(...)
      template <typename T, typename BoolPolicies, typename A0>
      struct use_terminal<qi::domain
          , terminal_ex<tag::stateful_tag<BoolPolicies, tag::bool_, T>
          , fusion::vector1<A0> > >
        : mpl::true_ {};
  
      // enables *lazy* custom bool_parser(...)
      template <typename T, typename BoolPolicies>
      struct use_lazy_terminal<
          qi::domain
        , tag::stateful_tag<BoolPolicies, tag::bool_, T>
        , 1 // arity
      > : mpl::true_ {};
  }}
  
  namespace boost { namespace spirit { namespace qi
  {
  #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
      using spirit::bool_;
      using spirit::true_;
      using spirit::false_;
      using spirit::lit;    // lit(true) is equivalent to true
  #endif
      using spirit::bool_type;
      using spirit::true_type;
      using spirit::false_type;
      using spirit::lit_type;
  
      namespace detail
      {
          template <typename T, typename BoolPolicies>
          struct bool_impl
          {
              template <typename Iterator, typename Attribute>
              static bool parse(Iterator& first, Iterator const& last
                , Attribute& attr, BoolPolicies const& p, bool allow_true = true
                , bool disallow_false = false)
              {
                  if (first == last)
                      return false;
  
  #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600))
                  p; // suppresses warning: C4100: 'p' : unreferenced formal parameter
  #endif
                  return (allow_true && p.parse_true(first, last, attr)) ||
                         (!disallow_false && p.parse_false(first, last, attr));
              }
          };
      }
  
      ///////////////////////////////////////////////////////////////////////////
      // This actual boolean parser
      ///////////////////////////////////////////////////////////////////////////
      template <typename T, typename BoolPolicies = bool_policies<T> >
      struct any_bool_parser
        : primitive_parser<any_bool_parser<T, BoolPolicies> >
      {
          template <typename Context, typename Iterator>
          struct attribute
          {
              typedef T type;
          };
  
          template <typename Iterator, typename Context
            , typename Skipper, typename Attribute>
          bool parse(Iterator& first, Iterator const& last
            , Context& /*context*/, Skipper const& skipper
            , Attribute& attr) const
          {
              typedef detail::bool_impl<T, BoolPolicies> extract;
              qi::skip_over(first, last, skipper);
              return extract::parse(first, last, attr, BoolPolicies());
          }
  
          template <typename Context>
          info what(Context& /*context*/) const
          {
              return info("boolean");
          }
      };
  
      template <typename T, typename BoolPolicies = bool_policies<T>
              , bool no_attribute = true>
      struct literal_bool_parser
        : primitive_parser<literal_bool_parser<T, BoolPolicies, no_attribute> >
      {
          template <typename Value>
          literal_bool_parser(Value const& n) : n_(n) {}
  
          template <typename Context, typename Iterator>
          struct attribute
            : mpl::if_c<no_attribute, unused_type, T>
          {};
  
          template <typename Iterator, typename Context
            , typename Skipper, typename Attribute>
          bool parse(Iterator& first, Iterator const& last
            , Context& /*context*/, Skipper const& skipper
            , Attribute& attr) const
          {
              typedef detail::bool_impl<T, BoolPolicies> extract;
              qi::skip_over(first, last, skipper);
              return extract::parse(first, last, attr, BoolPolicies(), n_, n_);
          }
  
          template <typename Context>
          info what(Context& /*context*/) const
          {
              return info("boolean");
          }
  
          T n_;
      };
  
      ///////////////////////////////////////////////////////////////////////////
      // Parser generators: make_xxx function (objects)
      ///////////////////////////////////////////////////////////////////////////
      template <typename T, typename Modifiers
              , typename Policies = bool_policies<T> >
      struct make_bool
      {
          typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
              no_case;
  
          typedef typename mpl::if_<
              mpl::and_<
                  no_case
                , is_same<bool_policies<T>, Policies>
              >
            , any_bool_parser<T, no_case_bool_policies<T> >
            , any_bool_parser<T, Policies> >::type
          result_type;
  
          result_type operator()(unused_type, unused_type) const
          {
              return result_type();
          }
      };
  
      template <typename T, typename Modifiers
              , typename Policies = bool_policies<T> >
      struct make_direct_bool
      {
          typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
              no_case;
  
          typedef typename mpl::if_<
              mpl::and_<
                  no_case
                , is_same<bool_policies<T>, Policies>
              >
            , literal_bool_parser<T, no_case_bool_policies<T>, false>
            , literal_bool_parser<T, Policies, false> >::type
          result_type;
  
          template <typename Terminal>
          result_type operator()(Terminal const& term, unused_type) const
          {
              return result_type(fusion::at_c<0>(term.args));
          }
      };
  
      template <typename T, typename Modifiers, bool b
              , typename Policies = bool_policies<T> >
      struct make_predefined_direct_bool
      {
          typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
              no_case;
  
          typedef typename mpl::if_<
              mpl::and_<
                  no_case
                , is_same<bool_policies<T>, Policies>
              >
            , literal_bool_parser<T, no_case_bool_policies<T>, false>
            , literal_bool_parser<T, Policies, false> >::type
          result_type;
  
          result_type operator()(unused_type, unused_type) const
          {
              return result_type(b);
          }
      };
  
      template <typename T, typename Modifiers
              , typename Policies = bool_policies<T> >
      struct make_literal_bool
      {
          typedef has_modifier<Modifiers, tag::char_code_base<tag::no_case> >
              no_case;
  
          typedef typename mpl::if_<
              mpl::and_<
                  no_case
                , is_same<bool_policies<T>, Policies>
              >
            , literal_bool_parser<T, no_case_bool_policies<T> >
            , literal_bool_parser<T, Policies> >::type
          result_type;
  
          template <typename Terminal>
          result_type operator()(Terminal const& term, unused_type) const
          {
              return result_type(fusion::at_c<0>(term.args));
          }
      };
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename Modifiers, typename A0>
      struct make_primitive<
            terminal_ex<tag::lit, fusion::vector1<A0> >
          , Modifiers, typename enable_if<is_same<A0, bool> >::type>
        : make_literal_bool<bool, Modifiers> {};
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename Modifiers>
      struct make_primitive<tag::false_, Modifiers>
        : make_predefined_direct_bool<bool, Modifiers, false>
      {};
  
      template <typename Modifiers>
      struct make_primitive<tag::true_, Modifiers>
        : make_predefined_direct_bool<bool, Modifiers, true>
      {};
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename T, typename Policies, typename Modifiers>
      struct make_primitive<
          tag::stateful_tag<Policies, tag::bool_, T>, Modifiers>
        : make_bool<T, Modifiers, Policies> {};
  
      template <typename T, typename Policies, typename A0, typename Modifiers>
      struct make_primitive<
          terminal_ex<tag::stateful_tag<Policies, tag::bool_, T>
        , fusion::vector1<A0> >, Modifiers>
        : make_direct_bool<T, Modifiers, Policies> {};
  
      ///////////////////////////////////////////////////////////////////////////
      template <typename Modifiers>
      struct make_primitive<tag::bool_, Modifiers>
        : make_bool<bool, Modifiers> {};
  
      template <typename Modifiers, typename A0>
      struct make_primitive<
          terminal_ex<tag::bool_
        , fusion::vector1<A0> >, Modifiers>
        : make_direct_bool<bool, Modifiers> {};
  }}}
  
  #endif
  