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 //  Copyright (c) 2001-2011 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_LEX_POSITION_TOKEN_MAY_13_2011_0846PM)
 #define BOOST_SPIRIT_LEX_POSITION_TOKEN_MAY_13_2011_0846PM
 
 #if defined(_MSC_VER)
 #pragma once
 #endif
 
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
 #include <boost/spirit/home/qi/detail/assign_to.hpp>
 #include <boost/spirit/home/support/attributes.hpp>
 #include <boost/spirit/home/support/argument.hpp>
 #include <boost/spirit/home/support/detail/lexer/generator.hpp>
 #include <boost/spirit/home/support/detail/lexer/rules.hpp>
 #include <boost/spirit/home/support/detail/lexer/consts.hpp>
 #include <boost/spirit/home/support/utree/utree_traits_fwd.hpp>
 #include <boost/spirit/home/lex/lexer/terminals.hpp>
 #include <boost/fusion/include/vector.hpp>
 #include <boost/fusion/include/at.hpp>
 #include <boost/fusion/include/value_at.hpp>
 #include <boost/variant.hpp>
 #include <boost/mpl/vector.hpp>
 #include <boost/mpl/bool.hpp>
 #include <boost/mpl/is_sequence.hpp>
 #include <boost/mpl/begin.hpp>
 #include <boost/mpl/insert.hpp>
 #include <boost/mpl/vector.hpp>
 #include <boost/mpl/if.hpp>
 #include <boost/mpl/or.hpp>
 #include <boost/type_traits/is_same.hpp>
 #include <boost/range/iterator_range_core.hpp>
 #include <boost/static_assert.hpp>
 
 #if defined(BOOST_SPIRIT_DEBUG)
 #include <iosfwd>
 #endif
 
 namespace boost { namespace spirit { namespace lex { namespace lexertl
 { 
     ///////////////////////////////////////////////////////////////////////////
     //
     //  The position_token is the type of the objects returned by the 
     //  iterator if it has been specified while instantiating the lexer object.
     //
     //    template parameters:
     //        Iterator        The type of the iterator used to access the
     //                        underlying character stream.
     //        AttributeTypes  A mpl sequence containing the types of all 
     //                        required different token values to be supported 
     //                        by this token type.
     //        HasState        A mpl::bool_ indicating, whether this token type
     //                        should support lexer states.
     //        Idtype          The type to use for the token id (defaults to 
     //                        std::size_t).
     //
     //  It is possible to use other token types with the spirit::lex 
     //  framework as well. If you plan to use a different type as your token 
     //  type, you'll need to expose the following things from your token type 
     //  to make it compatible with spirit::lex:
     //
     //    typedefs
     //        iterator_type   The type of the iterator used to access the
     //                        underlying character stream.
     //
     //        id_type         The type of the token id used.
     //
     //    methods
     //        default constructor
     //                        This should initialize the token as an end of 
     //                        input token.
     //        constructors    The prototype of the other required 
     //                        constructors should be:
     //
     //              token(int)
     //                        This constructor should initialize the token as 
     //                        an invalid token (not carrying any specific 
     //                        values)
     //
     //              where:  the int is used as a tag only and its value is 
     //                      ignored
     //
     //                        and:
     //
     //              token(Idtype id, std::size_t state, 
     //                    iterator_type first, iterator_type last);
     //
     //              where:  id:           token id
     //                      state:        lexer state this token was matched in
     //                      first, last:  pair of iterators marking the matched 
     //                                    range in the underlying input stream 
     //
     //        accessors
     //              id()      return the token id of the matched input sequence
     //              id(newid) set the token id of the token instance
     //
     //              state()   return the lexer state this token was matched in
     //
     //              value()   return the token value
     //
     //  Additionally, you will have to implement a couple of helper functions
     //  in the same namespace as the token type: a comparison operator==() to 
     //  compare your token instances, a token_is_valid() function and different 
     //  specializations of the Spirit customization point 
     //  assign_to_attribute_from_value as shown below.
     //
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator = char const*
       , typename AttributeTypes = mpl::vector0<>
       , typename HasState = mpl::true_
       , typename Idtype = std::size_t> 
     struct position_token;
 
     ///////////////////////////////////////////////////////////////////////////
     //  This specialization of the token type doesn't contain any item data and
     //  doesn't support working with lexer states. Although, like all other
     //  variants of position_token, it carries a pair of iterators marking the
     //  begin and the end of the matched character sequence.
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator, typename Idtype>
     struct position_token<Iterator, lex::omit, mpl::false_, Idtype>
     {
         typedef Iterator iterator_type;
         typedef iterator_range<iterator_type> iterpair_type;
         typedef mpl::false_ has_state;
         typedef Idtype id_type;
         typedef unused_type token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() 
           : id_(id_type(boost::lexer::npos)) {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : id_(id_type(0)) {}
 
         position_token(id_type id, std::size_t) 
           : id_(id) {}
 
         position_token(id_type id, std::size_t, token_value_type)
           : id_(id) {}
 
         position_token(id_type id, std::size_t, Iterator const& first
               , Iterator const& last)
           : id_(id), matched_(first, last) {}
 
         //  this default conversion operator is needed to allow the direct 
         //  usage of tokens in conjunction with the primitive parsers defined 
         //  in Qi
         operator id_type() const { return id_; }
 
         //  Retrieve or set the token id of this token instance. 
         id_type id() const { return id_; }
         void id(id_type newid) { id_ = newid; }
 
         std::size_t state() const { return 0; }   // always '0' (INITIAL state)
 
         bool is_valid() const 
         { 
             return 0 != id_ && id_type(boost::lexer::npos) != id_; 
         }
 
         // access the stored iterator range of the matched input sequence
         iterator_type begin() const { return matched_.begin(); }
         iterator_type end() const { return matched_.end(); }
 
         iterpair_type& matched() { return matched_; }
         iterpair_type const& matched() const { return matched_; }
 
         token_value_type& value() { static token_value_type u; return u; }
         token_value_type const& value() const { return unused; }
 
 #if BOOST_WORKAROUND(BOOST_MSVC, == 1600)
         // workaround for MSVC10 which has problems copying a default 
         // constructed iterator_range
         position_token& operator= (position_token const& rhs)
         {
             if (this != &rhs) 
             {
                 id_ = rhs.id_;
                 if (is_valid()) 
                     matched_ = rhs.matched_;
             }
             return *this;
         }
 #endif
 
     protected:
         id_type id_;              // token id, 0 if nothing has been matched
         iterpair_type matched_;   // matched input sequence
     };
 
 #if defined(BOOST_SPIRIT_DEBUG)
     template <typename Char, typename Traits, typename Iterator
       , typename AttributeTypes, typename HasState, typename Idtype> 
     inline std::basic_ostream<Char, Traits>& 
     operator<< (std::basic_ostream<Char, Traits>& os
       , position_token<Iterator, AttributeTypes, HasState, Idtype> const& t)
     {
         if (t.is_valid()) {
             Iterator end = t.end();
             for (Iterator it = t.begin(); it != end; ++it)
                 os << *it;
         }
         else {
             os << "<invalid token>";
         }
         return os;
     }
 #endif
 
     ///////////////////////////////////////////////////////////////////////////
     //  This specialization of the token type doesn't contain any item data but
     //  supports working with lexer states.
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator, typename Idtype>
     struct position_token<Iterator, lex::omit, mpl::true_, Idtype>
       : position_token<Iterator, lex::omit, mpl::false_, Idtype>
     {
     private:
         typedef position_token<Iterator, lex::omit, mpl::false_, Idtype> 
             base_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef Iterator iterator_type;
         typedef mpl::true_ has_state;
         typedef unused_type token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() : state_(boost::lexer::npos) {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : base_type(0), state_(boost::lexer::npos) {}
 
         position_token(id_type id, std::size_t state)
           : base_type(id, boost::lexer::npos), state_(state) {}
 
         position_token(id_type id, std::size_t state, token_value_type)
           : base_type(id, boost::lexer::npos, unused)
           , state_(state) {}
 
         position_token(id_type id, std::size_t state
               , Iterator const& first, Iterator const& last)
           : base_type(id, boost::lexer::npos, first, last)
           , state_(state) {}
 
         std::size_t state() const { return state_; }
 
 #if BOOST_WORKAROUND(BOOST_MSVC, == 1600)
         // workaround for MSVC10 which has problems copying a default 
         // constructed iterator_range
         position_token& operator= (position_token const& rhs)
         {
             if (this != &rhs) 
             {
                 this->base_type::operator=(static_cast<base_type const&>(rhs));
                 state_ = rhs.state_;
             }
             return *this;
         }
 #endif
 
     protected:
         std::size_t state_;      // lexer state this token was matched in
     };
 
     ///////////////////////////////////////////////////////////////////////////
     // These specializations for an empty attribute list cause all token 
     // instances to expose as it attribute the iterator_range pointing to the
     // matched input sequence.
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator, typename HasState, typename Idtype>
     struct position_token<Iterator, mpl::vector<>, HasState, Idtype>
       : position_token<Iterator, lex::omit, HasState, Idtype>
     {
     private:
         typedef position_token<Iterator, lex::omit, HasState, Idtype> base_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef typename base_type::iterator_type iterator_type;
         typedef typename base_type::iterpair_type iterpair_type;
         typedef HasState has_state;
         typedef iterpair_type token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : base_type(0) {}
 
         position_token(id_type id, std::size_t state)
           : base_type(id, state) {}
 
         position_token(id_type id, std::size_t state, token_value_type)
           : base_type(id, state, unused) {}
 
         position_token(id_type id, std::size_t state
               , Iterator const& first, Iterator const& last)
           : base_type(id, state, first, last) {}
 
         token_value_type& value() { return this->base_type::matched(); }
         token_value_type const& value() const { return this->base_type::matched(); }
     };
 
     template <typename Iterator, typename HasState, typename Idtype>
     struct position_token<Iterator, mpl::vector0<>, HasState, Idtype>
       : position_token<Iterator, lex::omit, HasState, Idtype>
     {
     private:
         typedef position_token<Iterator, lex::omit, HasState, Idtype> base_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef typename base_type::iterator_type iterator_type;
         typedef typename base_type::iterpair_type iterpair_type;
         typedef HasState has_state;
         typedef iterpair_type token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : base_type(0) {}
 
         position_token(id_type id, std::size_t state)
           : base_type(id, state) {}
 
         position_token(id_type id, std::size_t state, token_value_type)
           : base_type(id, state, unused) {}
 
         position_token(id_type id, std::size_t state
               , Iterator const& first, Iterator const& last)
           : base_type(id, state, first, last) {}
 
         token_value_type& value() { return this->base_type::matched(); }
         token_value_type const& value() const { return this->base_type::matched(); }
     };
 
     ///////////////////////////////////////////////////////////////////////////
     // These specializations for an attribute list of length one cause all token 
     // instances to expose the specified type as its attribute.
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator, typename Attribute, typename HasState
       , typename Idtype>
     struct position_token<Iterator, mpl::vector<Attribute>, HasState, Idtype>
       : position_token<Iterator, lex::omit, HasState, Idtype>
     {
     private:
         typedef position_token<Iterator, lex::omit, HasState, Idtype> base_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef typename base_type::iterator_type iterator_type;
         typedef typename base_type::iterpair_type iterpair_type;
         typedef HasState has_state;
         typedef boost::optional<Attribute> token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : base_type(0) {}
 
         position_token(id_type id, std::size_t state)
           : base_type(id, state) {}
 
         position_token(id_type id, std::size_t state, token_value_type const& v)
           : base_type(id, state, unused), value_(v) {}
 
         position_token(id_type id, std::size_t state
               , Iterator const& first, Iterator const& last)
           : base_type(id, state, first, last) {}
 
         token_value_type& value() { return value_; }
         token_value_type const& value() const { return value_; }
 
         bool has_value() const { return !!value_; }
 
 #if BOOST_WORKAROUND(BOOST_MSVC, == 1600)
         // workaround for MSVC10 which has problems copying a default 
         // constructed iterator_range
         position_token& operator= (position_token const& rhs)
         {
             if (this != &rhs) 
             {
                 this->base_type::operator=(static_cast<base_type const&>(rhs));
                 if (this->is_valid()) 
                     value_ = rhs.value_;
             }
             return *this;
         }
 #endif
 
     protected:
         token_value_type value_; // token value
     };
 
     template <typename Iterator, typename Attribute, typename HasState
       , typename Idtype>
     struct position_token<Iterator, mpl::vector1<Attribute>, HasState, Idtype>
       : position_token<Iterator, lex::omit, HasState, Idtype>
     {
     private:
         typedef position_token<Iterator, lex::omit, HasState, Idtype> base_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef typename base_type::iterator_type iterator_type;
         typedef typename base_type::iterpair_type iterpair_type;
         typedef HasState has_state;
         typedef boost::optional<Attribute> token_value_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() {}
 
         //  construct an invalid token
         explicit position_token(int) 
           : base_type(0) {}
 
         position_token(id_type id, std::size_t state)
           : base_type(id, state) {}
 
         position_token(id_type id, std::size_t state, token_value_type const& v)
           : base_type(id, state, unused), value_(v) {}
 
         position_token(id_type id, std::size_t state
               , Iterator const& first, Iterator const& last)
           : base_type(id, state, first, last) {}
 
         token_value_type& value() { return value_; }
         token_value_type const& value() const { return value_; }
 
         bool has_value() const { return value_; }
 
 #if BOOST_WORKAROUND(BOOST_MSVC, == 1600)
         // workaround for MSVC10 which has problems copying a default 
         // constructed iterator_range
         position_token& operator= (position_token const& rhs)
         {
             if (this != &rhs) 
             {
                 this->base_type::operator=(static_cast<base_type const&>(rhs));
                 if (this->is_valid()) 
                     value_ = rhs.value_;
             }
             return *this;
         }
 #endif
 
     protected:
         token_value_type value_; // token value
     };
 
     ///////////////////////////////////////////////////////////////////////////
     //  The generic version of the position_token type derives from the 
     //  specialization above and adds a single data member holding the item 
     //  data carried by the token instance.
     ///////////////////////////////////////////////////////////////////////////
     namespace detail
     {
         ///////////////////////////////////////////////////////////////////////
         //  Meta-function to calculate the type of the variant data item to be 
         //  stored with each token instance.
         //
         //  Note: The iterator pair needs to be the first type in the list of 
         //        types supported by the generated variant type (this is being 
         //        used to identify whether the stored data item in a particular 
         //        token instance needs to be converted from the pair of 
         //        iterators (see the first of the assign_to_attribute_from_value 
         //        specializations below).
         ///////////////////////////////////////////////////////////////////////
         template <typename IteratorPair, typename AttributeTypes>
         struct position_token_value_typesequence
         {
             typedef typename mpl::insert<
                 AttributeTypes
               , typename mpl::begin<AttributeTypes>::type
               , IteratorPair
             >::type sequence_type;
             typedef typename make_variant_over<sequence_type>::type type;
         };
 
         ///////////////////////////////////////////////////////////////////////
         //  The type of the data item stored with a token instance is defined 
         //  by the template parameter 'AttributeTypes' and may be:
         //  
         //     lex::omit:         no data item is stored with the token 
         //                        instance (this is handled by the 
         //                        specializations of the token class
         //                        below)
         //     mpl::vector0<>:    each token instance stores a pair of 
         //                        iterators pointing to the matched input 
         //                        sequence
         //     mpl::vector<...>:  each token instance stores a variant being 
         //                        able to store the pair of iterators pointing 
         //                        to the matched input sequence, or any of the 
         //                        types a specified in the mpl::vector<>
         //
         //  All this is done to ensure the token type is as small (in terms 
         //  of its byte-size) as possible.
         ///////////////////////////////////////////////////////////////////////
         template <typename IteratorPair, typename AttributeTypes>
         struct position_token_value
           : mpl::eval_if<
                 mpl::or_<
                     is_same<AttributeTypes, mpl::vector0<> >
                   , is_same<AttributeTypes, mpl::vector<> > >
               , mpl::identity<IteratorPair>
               , position_token_value_typesequence<IteratorPair, AttributeTypes> >
         {};
     }
 
     template <typename Iterator, typename AttributeTypes, typename HasState
       , typename Idtype>
     struct position_token 
       : position_token<Iterator, lex::omit, HasState, Idtype>
     {
     private: // precondition assertions
         BOOST_STATIC_ASSERT((mpl::is_sequence<AttributeTypes>::value || 
                             is_same<AttributeTypes, lex::omit>::value));
         typedef position_token<Iterator, lex::omit, HasState, Idtype> 
             base_type;
 
     protected: 
         //  If no additional token value types are given, the token will 
         //  hold no token value at all as the base class already has the 
         //  iterator pair of the matched range in the underlying input sequence. 
         //  Otherwise the token value is stored as a variant and will 
         //  initially hold an unused_type but is able to hold any of 
         //  the given data types as well. The conversion from the iterator pair 
         //  to the required data type is done when it is accessed for the first 
         //  time.
         typedef iterator_range<Iterator> iterpair_type;
 
     public:
         typedef typename base_type::id_type id_type;
         typedef typename detail::position_token_value<
             iterpair_type, AttributeTypes>::type token_value_type;
 
         typedef Iterator iterator_type;
 
         //  default constructed tokens correspond to EOI tokens
         position_token() {}
 
         //  construct an invalid token
         explicit position_token(int)
           : base_type(0) {}
 
         position_token(id_type id, std::size_t state, token_value_type const& value)
           : base_type(id, state, value), value_(value) {}
 
         position_token(id_type id, std::size_t state, Iterator const& first
               , Iterator const& last)
           : base_type(id, state, first, last)
           , value_(iterpair_type(first, last)) 
         {}
 
         token_value_type& value() { return value_; }
         token_value_type const& value() const { return value_; }
 
 #if BOOST_WORKAROUND(BOOST_MSVC, == 1600)
         // workaround for MSVC10 which has problems copying a default 
         // constructed iterator_range
         position_token& operator= (position_token const& rhs)
         {
             if (this != &rhs) 
             {
                 this->base_type::operator=(static_cast<base_type const&>(rhs));
                 if (this->is_valid()) 
                     value_ = rhs.value_;
             }
             return *this;
         }
 #endif
 
     protected:
         token_value_type value_; // token value, by default a pair of iterators
     };
 
     ///////////////////////////////////////////////////////////////////////////
     //  tokens are considered equal, if their id's match (these are unique)
     template <typename Iterator, typename AttributeTypes, typename HasState
       , typename Idtype>
     inline bool 
     operator== (position_token<Iterator, AttributeTypes, HasState, Idtype> const& lhs, 
                 position_token<Iterator, AttributeTypes, HasState, Idtype> const& rhs)
     {
         return lhs.id() == rhs.id();
     }
 
     ///////////////////////////////////////////////////////////////////////////
     //  This overload is needed by the multi_pass/functor_input_policy to 
     //  validate a token instance. It has to be defined in the same namespace 
     //  as the token class itself to allow ADL to find it.
     ///////////////////////////////////////////////////////////////////////////
     template <typename Iterator, typename AttributeTypes, typename HasState
       , typename Idtype>
     inline bool 
     token_is_valid(position_token<Iterator, AttributeTypes, HasState, Idtype> const& t)
     {
         return t.is_valid();
     }
 }}}}
 
 namespace boost { namespace spirit { namespace traits
 {
     ///////////////////////////////////////////////////////////////////////////
     //  We have to provide specializations for the customization point
     //  assign_to_attribute_from_value allowing to extract the needed value 
     //  from the token. 
     ///////////////////////////////////////////////////////////////////////////
 
     //  This is called from the parse function of token_def if the token_def
     //  has been defined to carry a special attribute type
     template <typename Attribute, typename Iterator, typename AttributeTypes
       , typename HasState, typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<
                 Iterator, AttributeTypes, HasState, Idtype> const& t
           , Attribute& attr)
         {
         //  The goal of this function is to avoid the conversion of the pair of
         //  iterators (to the matched character sequence) into the token value 
         //  of the required type being done more than once. For this purpose it 
         //  checks whether the stored value type is still the default one (pair 
         //  of iterators) and if yes, replaces the pair of iterators with the 
         //  converted value to be returned from subsequent calls.
 
             if (0 == t.value().which()) {
             //  first access to the token value
                 typedef iterator_range<Iterator> iterpair_type;
                 iterpair_type const& ip = t.matched();
 
             // Interestingly enough we use the assign_to() framework defined in 
             // Spirit.Qi allowing to convert the pair of iterators to almost any 
             // required type (assign_to(), if available, uses the standard Spirit 
             // parsers to do the conversion).
                 spirit::traits::assign_to(ip.begin(), ip.end(), attr);
 
             //  If you get an error during the compilation of the following 
             //  assignment expression, you probably forgot to list one or more 
             //  types used as token value types (in your token_def<...> 
             //  definitions) in your definition of the token class. I.e. any token 
             //  value type used for a token_def<...> definition has to be listed 
             //  during the declaration of the token type to use. For instance let's 
             //  assume we have two token_def's:
             //
             //      token_def<int> number; number = "...";
             //      token_def<std::string> identifier; identifier = "...";
             //
             //  Then you'll have to use the following token type definition 
             //  (assuming you are using the token class):
             //
             //      typedef mpl::vector<int, std::string> token_values;
             //      typedef token<base_iter_type, token_values> token_type;
             //
             //  where: base_iter_type is the iterator type used to expose the 
             //         underlying input stream.
             //
             //  This token_type has to be used as the second template parameter 
             //  to the lexer class:
             //
             //      typedef lexer<base_iter_type, token_type> lexer_type;
             //
             //  again, assuming you're using the lexer<> template for your 
             //  tokenization.
 
                 typedef lex::lexertl::position_token<
                     Iterator, AttributeTypes, HasState, Idtype> token_type;
                 spirit::traits::assign_to(
                     attr, const_cast<token_type&>(t).value());   // re-assign value
             }
             else {
             // reuse the already assigned value
                 spirit::traits::assign_to(get<Attribute>(t.value()), attr);
             }
         }
     };
 
     template <typename Attribute, typename Iterator, typename AttributeTypes
       , typename HasState, typename Idtype>
     struct assign_to_container_from_value<Attribute
           , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
       : assign_to_attribute_from_value<Attribute
           , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
     {};
 
     ///////////////////////////////////////////////////////////////////////////
     //  These are called from the parse function of token_def if the token type
     //  has no special attribute type assigned 
     template <typename Attribute, typename Iterator, typename HasState
       , typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, mpl::vector0<>, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<
                 Iterator, mpl::vector0<>, HasState, Idtype> const& t
           , Attribute& attr)
         {
             //  The default type returned by the token_def parser component (if 
             //  it has no token value type assigned) is the pair of iterators 
             //  to the matched character sequence.
             spirit::traits::assign_to(t.begin(), t.end(), attr);
         }
     };
 
 //     template <typename Attribute, typename Iterator, typename HasState
 //       , typename Idtype>
 //     struct assign_to_container_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector0<>, HasState, Idtype> >
 //       : assign_to_attribute_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector0<>, HasState, Idtype> >
 //     {};
 
     // same as above but using mpl::vector<> instead of mpl::vector0<>
     template <typename Attribute, typename Iterator, typename HasState
       , typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, mpl::vector<>, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<
                 Iterator, mpl::vector<>, HasState, Idtype> const& t
           , Attribute& attr)
         {
             //  The default type returned by the token_def parser component (if 
             //  it has no token value type assigned) is the pair of iterators 
             //  to the matched character sequence.
             spirit::traits::assign_to(t.begin(), t.end(), attr);
         }
     };
 
 //     template <typename Attribute, typename Iterator, typename HasState
 //       , typename Idtype>
 //     struct assign_to_container_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector<>, HasState, Idtype> >
 //       : assign_to_attribute_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector<>, HasState, Idtype> >
 //     {};
 
     ///////////////////////////////////////////////////////////////////////////
     //  These are called from the parse function of token_def if the token type
     //  has no special attribute type assigned 
     template <typename Attribute, typename Iterator, typename Attr
       , typename HasState, typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, mpl::vector1<Attr>, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<
                 Iterator, mpl::vector1<Attr>, HasState, Idtype> const& t
           , Attribute& attr)
         {
         //  The goal of this function is to avoid the conversion of the pair of
         //  iterators (to the matched character sequence) into the token value 
         //  of the required type being done more than once.
 
             if (!t.has_value()) {
             //  first access to the token value
                 typedef iterator_range<Iterator> iterpair_type;
                 iterpair_type const& ip = t.matched();
 
             // Interestingly enough we use the assign_to() framework defined in 
             // Spirit.Qi allowing to convert the pair of iterators to almost any 
             // required type (assign_to(), if available, uses the standard Spirit 
             // parsers to do the conversion).
                 spirit::traits::assign_to(ip.begin(), ip.end(), attr);
 
             // Re-assign the attribute to the stored value
                 typedef lex::lexertl::position_token<
                     Iterator, mpl::vector1<Attr>, HasState, Idtype> token_type;
                 spirit::traits::assign_to(
                     attr, const_cast<token_type&>(t).value());
             }
             else {
             // reuse the already assigned value
                 spirit::traits::assign_to(t.value(), attr);
             }
         }
     };
 
 //     template <typename Attribute, typename Iterator, typename Attr
 //       , typename HasState, typename Idtype>
 //     struct assign_to_container_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector1<Attr>, HasState, Idtype> >
 //       : assign_to_attribute_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector1<Attr>, HasState, Idtype> >
 //     {};
 
     // same as above but using mpl::vector<Attr> instead of mpl::vector1<Attr>
     template <typename Attribute, typename Iterator, typename Attr
       , typename HasState, typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, mpl::vector<Attr>, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<
                 Iterator, mpl::vector<Attr>, HasState, Idtype> const& t
           , Attribute& attr)
         {
         //  The goal of this function is to avoid the conversion of the pair of
         //  iterators (to the matched character sequence) into the token value 
         //  of the required type being done more than once.
 
             if (!t.has_value()) {
             //  first access to the token value
                 typedef iterator_range<Iterator> iterpair_type;
                 iterpair_type const& ip = t.matched();
 
             // Interestingly enough we use the assign_to() framework defined in 
             // Spirit.Qi allowing to convert the pair of iterators to almost any 
             // required type (assign_to(), if available, uses the standard Spirit 
             // parsers to do the conversion).
                 spirit::traits::assign_to(ip.begin(), ip.end(), attr);
 
             // Re-assign the attribute to the stored value
                 typedef lex::lexertl::position_token<
                     Iterator, mpl::vector<Attr>, HasState, Idtype> token_type;
                 spirit::traits::assign_to(
                     attr, const_cast<token_type&>(t).value());
             }
             else {
             // reuse the already assigned value
                 spirit::traits::assign_to(t.value(), attr);
             }
         }
     };
 
 //     template <typename Attribute, typename Iterator, typename Attr
 //       , typename HasState, typename Idtype>
 //     struct assign_to_container_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector<Attr>, HasState, Idtype> >
 //       : assign_to_attribute_from_value<Attribute
 //           , lex::lexertl::position_token<Iterator, mpl::vector<Attr>, HasState, Idtype> >
 //     {};
 
     //  This is called from the parse function of token_def if the token type
     //  has been explicitly omitted (i.e. no attribute value is used), which
     //  essentially means that every attribute gets initialized using default 
     //  constructed values.
     template <typename Attribute, typename Iterator, typename HasState
       , typename Idtype>
     struct assign_to_attribute_from_value<Attribute
       , lex::lexertl::position_token<Iterator, lex::omit, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<Iterator, lex::omit, HasState, Idtype> const&
           , Attribute&)
         {
             // do nothing
         }
     };
 
     template <typename Attribute, typename Iterator, typename HasState
       , typename Idtype>
     struct assign_to_container_from_value<Attribute
           , lex::lexertl::position_token<Iterator, lex::omit, HasState, Idtype> >
       : assign_to_attribute_from_value<Attribute
           , lex::lexertl::position_token<Iterator, lex::omit, HasState, Idtype> >
     {};
 
     //  This is called from the parse function of lexer_def_
     template <typename Iterator, typename AttributeTypes, typename HasState
       , typename Idtype_, typename Idtype>
     struct assign_to_attribute_from_value<
         fusion::vector2<Idtype_, iterator_range<Iterator> >
       , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
     {
         static void 
         call(lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> const& t
           , fusion::vector2<Idtype_, iterator_range<Iterator> >& attr)
         {
             //  The type returned by the lexer_def_ parser components is a 
             //  fusion::vector containing the token id of the matched token 
             //  and the pair of iterators to the matched character sequence.
             typedef iterator_range<Iterator> iterpair_type;
             typedef fusion::vector2<Idtype_, iterator_range<Iterator> > 
                 attribute_type;
 
             iterpair_type const& ip = t.matched();
             attr = attribute_type(t.id(), ip);
         }
     };
 
     template <typename Iterator, typename AttributeTypes, typename HasState
       , typename Idtype_, typename Idtype>
     struct assign_to_container_from_value<
             fusion::vector2<Idtype_, iterator_range<Iterator> >
           , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
       : assign_to_attribute_from_value<
             fusion::vector2<Idtype_, iterator_range<Iterator> >
           , lex::lexertl::position_token<Iterator, AttributeTypes, HasState, Idtype> >
     {};
 
     ///////////////////////////////////////////////////////////////////////////
     // Overload debug output for a single token, this integrates lexer tokens 
     // with Qi's simple_trace debug facilities
     template <typename Iterator, typename Attribute, typename HasState
       , typename Idtype>
     struct token_printer_debug<
         lex::lexertl::position_token<Iterator, Attribute, HasState, Idtype> >
     {
         typedef lex::lexertl::position_token<Iterator, Attribute, HasState, Idtype> token_type;
 
         template <typename Out>
         static void print(Out& out, token_type const& val) 
         {
             out << '[';
             spirit::traits::print_token(out, val.value());
             out << ']';
         }
     };
 }}}
 
 #endif

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