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 /*=============================================================================
     Boost.Wave: A Standard compliant C++ preprocessor library
 
     Definition of the preprocessor iterator
 
     http://www.boost.org/
 
     Copyright (c) 2001-2012 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_CPP_ITERATOR_HPP_175CA88F_7273_43FA_9039_BCF7459E1F29_INCLUDED)
 #define BOOST_CPP_ITERATOR_HPP_175CA88F_7273_43FA_9039_BCF7459E1F29_INCLUDED
 
 #include <string>
 #include <vector>
 #include <list>
 #include <cstdlib>
 #include <cctype>
 
 #include <boost/assert.hpp>
 #include <boost/shared_ptr.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/filesystem/operations.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/spirit/include/classic_multi_pass.hpp>
 #include <boost/spirit/include/classic_parse_tree_utils.hpp>
 
 #include <boost/wave/wave_config.hpp>
 #include <boost/pool/pool_alloc.hpp>
 
 #include <boost/wave/util/insert_whitespace_detection.hpp>
 #include <boost/wave/util/macro_helpers.hpp>
 #include <boost/wave/util/cpp_macromap_utils.hpp>
 #include <boost/wave/util/interpret_pragma.hpp>
 #include <boost/wave/util/transform_iterator.hpp>
 #include <boost/wave/util/functor_input.hpp>
 #include <boost/wave/util/filesystem_compatibility.hpp>
 
 #include <boost/wave/grammars/cpp_grammar_gen.hpp>
 #include <boost/wave/grammars/cpp_expression_grammar_gen.hpp>
 #if BOOST_WAVE_ENABLE_COMMANDLINE_MACROS != 0
 #include <boost/wave/grammars/cpp_predef_macros_gen.hpp>
 #endif
 
 #include <boost/wave/whitespace_handling.hpp>
 #include <boost/wave/cpp_iteration_context.hpp>
 #include <boost/wave/cpp_exceptions.hpp>
 #include <boost/wave/language_support.hpp>
 
 // this must occur after all of the includes and before any code appears
 #ifdef BOOST_HAS_ABI_HEADERS
 #include BOOST_ABI_PREFIX
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 namespace boost {
 namespace wave {
 namespace util {
 
 ///////////////////////////////////////////////////////////////////////////////
 // retrieve the macro name from the parse tree
 template <
     typename ContextT, typename ParseNodeT, typename TokenT,
     typename PositionT
 >
 inline bool
 retrieve_macroname(ContextT& ctx, ParseNodeT const &node,
     boost::spirit::classic::parser_id id, TokenT &macroname, PositionT& act_pos,
     bool update_position)
 {
     ParseNodeT const* name_node = 0;
 
     using boost::spirit::classic::find_node;
     if (!find_node(node, id, &name_node))
     {
         // ill formed define statement (unexpected, should not happen)
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_define_statement,
             "bad parse tree (unexpected)", act_pos);
         return false;
     }
 
     typename ParseNodeT::children_t const& children = name_node->children;
 
     if (0 == children.size() ||
         children.front().value.begin() == children.front().value.end())
     {
         // ill formed define statement (unexpected, should not happen)
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_define_statement,
             "bad parse tree (unexpected)", act_pos);
         return false;
     }
 
     // retrieve the macro name
     macroname = *children.front().value.begin();
     if (update_position) {
         macroname.set_position(act_pos);
         act_pos.set_column(act_pos.get_column() + macroname.get_value().size());
     }
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // retrieve the macro parameters or the macro definition from the parse tree
 template <typename ParseNodeT, typename ContainerT, typename PositionT>
 inline bool
 retrieve_macrodefinition(
     ParseNodeT const &node, boost::spirit::classic::parser_id id,
     ContainerT &macrodefinition, PositionT& act_pos, bool update_position)
 {
     using namespace boost::wave;
     typedef typename ParseNodeT::const_tree_iterator const_tree_iterator;
 
     // find macro parameters/macro definition inside the parse tree
     std::pair<const_tree_iterator, const_tree_iterator> nodes;
 
     using boost::spirit::classic::get_node_range;
     if (get_node_range(node, id, nodes)) {
         // copy all parameters to the supplied container
         typename ContainerT::iterator last_nonwhite = macrodefinition.end();
         const_tree_iterator end = nodes.second;
 
         for (const_tree_iterator cit = nodes.first; cit != end; ++cit) {
             if ((*cit).value.begin() != (*cit).value.end()) {
                 typename ContainerT::iterator inserted = macrodefinition.insert(
                     macrodefinition.end(), *(*cit).value.begin());
 
                 if (!IS_CATEGORY(macrodefinition.back(), WhiteSpaceTokenType) &&
                     T_NEWLINE != token_id(macrodefinition.back()) &&
                     T_EOF != token_id(macrodefinition.back()))
                 {
                     last_nonwhite = inserted;
                 }
 
                 if (update_position) {
                     (*inserted).set_position(act_pos);
                     act_pos.set_column(
                         act_pos.get_column() + (*inserted).get_value().size());
                 }
             }
         }
 
         // trim trailing whitespace (leading whitespace is trimmed by the grammar)
         if (last_nonwhite != macrodefinition.end()) {
             if (update_position) {
                 act_pos.set_column((*last_nonwhite).get_position().get_column() +
                     (*last_nonwhite).get_value().size());
             }
             macrodefinition.erase(++last_nonwhite, macrodefinition.end());
         }
         return true;
     }
     return false;
 }
 
 #if BOOST_WAVE_ENABLE_COMMANDLINE_MACROS != 0
 ///////////////////////////////////////////////////////////////////////////////
 //  add an additional predefined macro given by a string (MACRO(x)=definition)
 template <typename ContextT>
 bool add_macro_definition(ContextT &ctx, std::string macrostring,
     bool is_predefined, boost::wave::language_support language)
 {
     typedef typename ContextT::token_type token_type;
     typedef typename ContextT::lexer_type lexer_type;
     typedef typename token_type::position_type position_type;
     typedef boost::wave::grammars::predefined_macros_grammar_gen<lexer_type>
         predef_macros_type;
 
     using namespace boost::wave;
     using namespace std;    // isspace is in std namespace for some systems
 
     // skip leading whitespace
     std::string::iterator begin = macrostring.begin();
     std::string::iterator end = macrostring.end();
 
     while(begin != end && isspace(*begin))
         ++begin;
 
     // parse the macro definition
     position_type act_pos("<command line>");
     boost::spirit::classic::tree_parse_info<lexer_type> hit =
         predef_macros_type::parse_predefined_macro(
             lexer_type(begin, end, position_type(), language), lexer_type());
 
     if (!hit.match || (!hit.full && T_EOF != token_id(*hit.stop))) {
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_macro_definition,
             macrostring.c_str(), act_pos);
         return false;
     }
 
     // retrieve the macro definition from the parse tree
     token_type macroname;
     std::vector<token_type> macroparameters;
     typename ContextT::token_sequence_type macrodefinition;
     bool has_parameters = false;
 
     if (!boost::wave::util::retrieve_macroname(ctx, *hit.trees.begin(),
             BOOST_WAVE_PLAIN_DEFINE_ID, macroname, act_pos, true))
         return false;
     has_parameters = boost::wave::util::retrieve_macrodefinition(*hit.trees.begin(),
         BOOST_WAVE_MACRO_PARAMETERS_ID, macroparameters, act_pos, true);
     boost::wave::util::retrieve_macrodefinition(*hit.trees.begin(),
         BOOST_WAVE_MACRO_DEFINITION_ID, macrodefinition, act_pos, true);
 
     // get rid of trailing T_EOF
     if (!macrodefinition.empty() && token_id(macrodefinition.back()) == T_EOF)
         macrodefinition.pop_back();
 
     //  If no macrodefinition is given, and the macro string does not end with a
     //  '=', then the macro should be defined with the value '1'
     if (macrodefinition.empty() && '=' != macrostring[macrostring.size()-1])
         macrodefinition.push_back(token_type(T_INTLIT, "1", act_pos));
 
     // add the new macro to the macromap
     return ctx.add_macro_definition(macroname, has_parameters, macroparameters,
         macrodefinition, is_predefined);
 }
 #endif // BOOST_WAVE_ENABLE_COMMANDLINE_MACROS != 0
 
 ///////////////////////////////////////////////////////////////////////////////
 }   // namespace util
 
 ///////////////////////////////////////////////////////////////////////////////
 //  forward declaration
 template <typename ContextT> class pp_iterator;
 
 namespace impl {
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  pp_iterator_functor
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 class pp_iterator_functor {
 
 public:
     // interface to the boost::spirit::classic::iterator_policies::functor_input policy
     typedef typename ContextT::token_type               result_type;
 
     //  eof token
     static result_type const eof;
 
 private:
     // type of a token sequence
     typedef typename ContextT::token_sequence_type      token_sequence_type;
 
     typedef typename ContextT::lexer_type               lexer_type;
     typedef typename result_type::string_type           string_type;
     typedef typename result_type::position_type         position_type;
     typedef boost::wave::grammars::cpp_grammar_gen<lexer_type, token_sequence_type>
         cpp_grammar_type;
 
     //  iteration context related types (an iteration context represents a current
     //  position in an included file)
     typedef base_iteration_context<ContextT, lexer_type>
         base_iteration_context_type;
     typedef iteration_context<ContextT, lexer_type> iteration_context_type;
 
     // parse tree related types
     typedef typename cpp_grammar_type::node_factory_type node_factory_type;
     typedef boost::spirit::classic::tree_parse_info<lexer_type, node_factory_type>
         tree_parse_info_type;
     typedef boost::spirit::classic::tree_match<lexer_type, node_factory_type>
         parse_tree_match_type;
     typedef typename parse_tree_match_type::node_t       parse_node_type;       // tree_node<node_val_data<> >
     typedef typename parse_tree_match_type::parse_node_t parse_node_value_type; // node_val_data<>
     typedef typename parse_tree_match_type::container_t  parse_tree_type;       // parse_node_type::children_t
 
 public:
     template <typename IteratorT>
     pp_iterator_functor(ContextT &ctx_, IteratorT const &first_,
             IteratorT const &last_, typename ContextT::position_type const &pos_)
     :   ctx(ctx_),
         iter_ctx(new base_iteration_context_type(ctx,
                 lexer_type(first_, last_, pos_,
                     boost::wave::enable_prefer_pp_numbers(ctx.get_language())),
                 lexer_type(),
                 pos_.get_file().c_str()
             )),
         seen_newline(true), skipped_newline(false),
         must_emit_line_directive(false), act_pos(ctx_.get_main_pos()),
         whitespace(boost::wave::need_insert_whitespace(ctx.get_language()))
     {
         act_pos.set_file(pos_.get_file());
 #if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
         ctx_.set_current_filename(pos_.get_file().c_str());
 #endif
         iter_ctx->emitted_lines = (unsigned int)(-1);   // force #line directive
     }
 
     // get the next preprocessed token
     result_type const &operator()();
 
     // get the last recognized token (for error processing etc.)
     result_type const &current_token() const { return act_token; }
 
 protected:
     friend class pp_iterator<ContextT>;
     bool on_include_helper(char const *t, char const *s, bool is_system,
         bool include_next);
 
 protected:
     result_type const &get_next_token();
     result_type const &pp_token();
 
     template <typename IteratorT>
     bool extract_identifier(IteratorT &it);
     template <typename IteratorT>
     bool ensure_is_last_on_line(IteratorT& it, bool call_hook = true);
     template <typename IteratorT>
     bool skip_to_eol_with_check(IteratorT &it, bool call_hook = true);
 
     bool pp_directive();
     template <typename IteratorT>
     bool handle_pp_directive(IteratorT &it);
     bool dispatch_directive(tree_parse_info_type const &hit,
         result_type const& found_directive,
         token_sequence_type const& found_eoltokens);
     void replace_undefined_identifiers(token_sequence_type &expanded);
 
     void on_include(string_type const &s, bool is_system, bool include_next);
     void on_include(typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end, bool include_next);
 
     void on_define(parse_node_type const &node);
     void on_undefine(lexer_type const &it);
 
     void on_ifdef(result_type const& found_directive,
         typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
     void on_ifndef(result_type const& found_directive,
         typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
     void on_else();
     void on_endif();
     void on_illformed(typename result_type::string_type s);
 
     void on_line(typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
     void on_if(result_type const& found_directive,
         typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
     void on_elif(result_type const& found_directive,
         typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
     void on_error(typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
 #if BOOST_WAVE_SUPPORT_WARNING_DIRECTIVE != 0
     void on_warning(typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
 #endif
     bool on_pragma(typename parse_tree_type::const_iterator const &begin,
         typename parse_tree_type::const_iterator const &end);
 
     bool emit_line_directive();
     bool returned_from_include();
 
     bool interpret_pragma(token_sequence_type const &pragma_body,
         token_sequence_type &result);
 
 private:
     ContextT &ctx;              // context, this iterator is associated with
     boost::shared_ptr<base_iteration_context_type> iter_ctx;
 
     bool seen_newline;              // needed for recognizing begin of line
     bool skipped_newline;           // a newline has been skipped since last one
     bool must_emit_line_directive;  // must emit a line directive
     result_type act_token;          // current token
     typename result_type::position_type &act_pos;   // current fileposition (references the macromap)
 
     token_sequence_type unput_queue;     // tokens to be preprocessed again
     token_sequence_type pending_queue;   // tokens already preprocessed
 
     // detect whether to insert additional whitespace in between two adjacent
     // tokens, which otherwise would form a different token type, if
     // re-tokenized
     boost::wave::util::insert_whitespace_detection whitespace;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 //  eof token
 template <typename ContextT>
 typename pp_iterator_functor<ContextT>::result_type const
     pp_iterator_functor<ContextT>::eof;
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  returned_from_include()
 //
 //      Tests if it is necessary to pop the include file context (eof inside
 //      a file was reached). If yes, it pops this context. Preprocessing will
 //      continue with the next outer file scope.
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::returned_from_include()
 {
     if (iter_ctx->first == iter_ctx->last && ctx.get_iteration_depth() > 0) {
         // call the include policy trace function
         ctx.get_hooks().returning_from_include_file(ctx.derived());
 
     // restore the previous iteration context after finishing the preprocessing
     // of the included file
         BOOST_WAVE_STRINGTYPE oldfile = iter_ctx->real_filename;
         position_type old_pos (act_pos);
 
         // if this file has include guards handle it as if it had a #pragma once
 #if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
         if (need_include_guard_detection(ctx.get_language())) {
             std::string guard_name;
             if (iter_ctx->first.has_include_guards(guard_name))
                 ctx.add_pragma_once_header(ctx.get_current_filename(), guard_name);
         }
 #endif
         iter_ctx = ctx.pop_iteration_context();
 
         must_emit_line_directive = true;
         iter_ctx->emitted_lines = (unsigned int)(-1);   // force #line directive
         seen_newline = true;
 
         // restore current file position
         act_pos.set_file(iter_ctx->filename);
         act_pos.set_line(iter_ctx->line);
         act_pos.set_column(0);
 
         // restore the actual current file and directory
 #if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
         namespace fs = boost::filesystem;
         fs::path rfp(wave::util::create_path(iter_ctx->real_filename.c_str()));
         std::string real_filename(rfp.string());
         ctx.set_current_filename(real_filename.c_str());
 #endif
         ctx.set_current_directory(iter_ctx->real_filename.c_str());
         ctx.set_current_relative_filename(iter_ctx->real_relative_filename.c_str());
 
         // ensure the integrity of the #if/#endif stack
         // report unbalanced #if/#endif now to make it possible to recover properly
         if (iter_ctx->if_block_depth != ctx.get_if_block_depth()) {
             using boost::wave::util::impl::escape_lit;
             BOOST_WAVE_STRINGTYPE msg(escape_lit(oldfile));
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, unbalanced_if_endif,
                 msg.c_str(), old_pos);
         }
         return true;
     }
     return false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  operator()(): get the next preprocessed token
 //
 //      throws a preprocess_exception, if appropriate
 //
 ///////////////////////////////////////////////////////////////////////////////
 namespace impl {
 
     //  It may be necessary to emit a #line directive either
     //  - when comments need to be preserved: if the current token is not a
     //    whitespace, except comments
     //  - when comments are to be skipped: if the current token is not a
     //    whitespace token.
     template <typename ContextT>
     bool consider_emitting_line_directive(ContextT const& ctx, token_id id)
     {
         if (need_preserve_comments(ctx.get_language()))
         {
             if (!IS_CATEGORY(id, EOLTokenType) && !IS_CATEGORY(id, EOFTokenType))
             {
                 return true;
             }
         }
         if (!IS_CATEGORY(id, WhiteSpaceTokenType) &&
             !IS_CATEGORY(id, EOLTokenType) && !IS_CATEGORY(id, EOFTokenType))
         {
             return true;
         }
         return false;
     }
 }
 
 template <typename ContextT>
 inline typename pp_iterator_functor<ContextT>::result_type const &
 pp_iterator_functor<ContextT>::operator()()
 {
     using namespace boost::wave;
 
     // make sure the cwd has been initialized
     ctx.init_context();
 
     // loop over skip able whitespace until something significant is found
     bool was_seen_newline = seen_newline;
     bool was_skipped_newline = skipped_newline;
     token_id id = T_UNKNOWN;
 
     try {   // catch lexer exceptions
         do {
             if (skipped_newline) {
                 was_skipped_newline = true;
                 skipped_newline = false;
             }
 
             // get_next_token assigns result to act_token member
             get_next_token();
 
             // if comments shouldn't be preserved replace them with newlines
             id = token_id(act_token);
             if (!need_preserve_comments(ctx.get_language()) &&
                 (T_CPPCOMMENT == id || context_policies::util::ccomment_has_newline(act_token)))
             {
                 act_token.set_token_id(id = T_NEWLINE);
                 act_token.set_value("\n");
             }
 
             if (IS_CATEGORY(id, EOLTokenType))
                 seen_newline = true;
 
         } while (ctx.get_hooks().may_skip_whitespace(ctx.derived(), act_token, skipped_newline));
     }
     catch (boost::wave::cpplexer::lexing_exception const& e) {
         // dispatch any lexer exceptions to the context hook function
         ctx.get_hooks().throw_exception(ctx.derived(), e);
         return act_token;
     }
 
     // restore the accumulated skipped_newline state for next invocation
     if (was_skipped_newline)
         skipped_newline = true;
 
     // if there were skipped any newlines, we must emit a #line directive
     if ((must_emit_line_directive || (was_seen_newline && skipped_newline)) &&
         impl::consider_emitting_line_directive(ctx, id))
     {
         // must emit a #line directive
         if (need_emit_line_directives(ctx.get_language()) && emit_line_directive())
         {
             skipped_newline = false;
             ctx.get_hooks().may_skip_whitespace(ctx.derived(), act_token, skipped_newline);     // feed ws eater FSM
             id = token_id(act_token);
         }
     }
 
     // cleanup of certain tokens required
     seen_newline = false;
     switch (id) {
     case T_NONREPLACABLE_IDENTIFIER:
         act_token.set_token_id(id = T_IDENTIFIER);
         break;
 
     case T_GENERATEDNEWLINE:  // was generated by emit_line_directive()
         act_token.set_token_id(id = T_NEWLINE);
         ++iter_ctx->emitted_lines;
         seen_newline = true;
         break;
 
     case T_NEWLINE:
     case T_CPPCOMMENT:
         seen_newline = true;
         ++iter_ctx->emitted_lines;
         break;
 
 #if BOOST_WAVE_SUPPORT_CPP0X != 0
     case T_RAWSTRINGLIT:
         iter_ctx->emitted_lines +=
             context_policies::util::rawstring_count_newlines(act_token);
         break;
 #endif
 
     case T_CCOMMENT:          // will come here only if whitespace is preserved
         iter_ctx->emitted_lines +=
             context_policies::util::ccomment_count_newlines(act_token);
         break;
 
     case T_PP_NUMBER:        // re-tokenize the pp-number
         {
             token_sequence_type rescanned;
 
             std::string pp_number(
                 util::to_string<std::string>(act_token.get_value()));
 
             lexer_type it = lexer_type(pp_number.begin(),
                 pp_number.end(), act_token.get_position(),
                 ctx.get_language());
             lexer_type end = lexer_type();
 
             for (/**/; it != end && T_EOF != token_id(*it); ++it)
                 rescanned.push_back(*it);
 
             pending_queue.splice(pending_queue.begin(), rescanned);
             act_token = pending_queue.front();
             id = token_id(act_token);
             pending_queue.pop_front();
         }
         break;
 
     case T_EOF:
         seen_newline = true;
         break;
 
     default:    // make sure whitespace at line begin keeps seen_newline status
         if (IS_CATEGORY(id, WhiteSpaceTokenType))
             seen_newline = was_seen_newline;
         break;
     }
 
     if (token_is_valid(act_token) && whitespace.must_insert(id, act_token.get_value())) {
         // must insert some whitespace into the output stream to avoid adjacent
         // tokens, which would form different (and wrong) tokens
         whitespace.shift_tokens(T_SPACE);
         pending_queue.push_front(act_token);        // push this token back
         return act_token = result_type(T_SPACE,
             typename result_type::string_type(" "),
             act_token.get_position());
     }
     whitespace.shift_tokens(id);
     return ctx.get_hooks().generated_token(ctx.derived(), act_token);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline typename pp_iterator_functor<ContextT>::result_type const &
 pp_iterator_functor<ContextT>::get_next_token()
 {
     using namespace boost::wave;
 
     // if there is something in the unput_queue, then return the next token from
     // there (all tokens in the queue are preprocessed already)
     if (!pending_queue.empty() || !unput_queue.empty())
         return pp_token();      // return next token
 
     // test for EOF, if there is a pending input context, pop it back and continue
     // parsing with it
     bool returned_from_include_file = returned_from_include();
 
     // try to generate the next token
     if (iter_ctx->first != iter_ctx->last) {
         do {
             // If there are pending tokens in the queue, we'll have to return
             // these. This may happen from a #pragma directive, which got replaced
             // by some token sequence.
             if (!pending_queue.empty()) {
                 util::on_exit::pop_front<token_sequence_type>
                     pop_front_token(pending_queue);
 
                 return act_token = pending_queue.front();
             }
 
             // adjust the current position (line and column)
             bool was_seen_newline = seen_newline || returned_from_include_file;
 
             // fetch the current token
             act_token = *iter_ctx->first;
             act_pos = act_token.get_position();
 
             // act accordingly on the current token
             token_id id = token_id(act_token);
 
             if (T_EOF == id) {
                 // returned from an include file, continue with the next token
                 whitespace.shift_tokens(T_EOF);
                 ++iter_ctx->first;
 
                 // now make sure this line has a newline
                 if ((!seen_newline || act_pos.get_column() > 1) &&
                     !need_single_line(ctx.get_language()))
                 {
                     if (need_no_newline_at_end_of_file(ctx.get_language()))
                     {
                         seen_newline = true;
                         pending_queue.push_back(
                             result_type(T_NEWLINE, "\n", act_pos)
                         );
                     }
                     else
                     {
                         // warn, if this file does not end with a newline
                         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                             last_line_not_terminated, "", act_pos);
                     }
                 }
                 continue;   // if this is the main file, the while loop breaks
             }
             else if (T_NEWLINE == id || T_CPPCOMMENT == id) {
                 // a newline is to be returned ASAP, a C++ comment too
                 // (the C++ comment token includes the trailing newline)
                 seen_newline = true;
                 ++iter_ctx->first;
 
                 if (!ctx.get_if_block_status()) {
                     // skip this token because of the disabled #if block
                     whitespace.shift_tokens(id);  // whitespace controller
                     util::impl::call_skipped_token_hook(ctx, act_token);
                     continue;
                 }
                 return act_token;
             }
             seen_newline = false;
 
             if (was_seen_newline && pp_directive()) {
                 // a pp directive was found
 //                 pending_queue.push_back(result_type(T_NEWLINE, "\n", act_pos));
 //                 seen_newline = true;
 //                 must_emit_line_directive = true;
                 if (iter_ctx->first == iter_ctx->last)
                 {
                     seen_newline = true;
                     act_token = result_type(T_NEWLINE, "\n", act_pos);
                 }
 
                 // loop to the next token to analyze
                 // simply fall through, since the iterator was already adjusted
                 // correctly
             }
             else if (ctx.get_if_block_status()) {
                 // preprocess this token, eat up more, if appropriate, return
                 // the next preprocessed token
                 return pp_token();
             }
             else {
                 // compilation condition is false: if the current token is a
                 // newline, account for it, otherwise discard the actual token and
                 // try the next one
                 if (T_NEWLINE == token_id(act_token)) {
                     seen_newline = true;
                     must_emit_line_directive = true;
                 }
 
                 // next token
                 util::impl::call_skipped_token_hook(ctx, act_token);
                 ++iter_ctx->first;
             }
 
         } while ((iter_ctx->first != iter_ctx->last) ||
                  (returned_from_include_file = returned_from_include()));
 
         // overall eof reached
         if (ctx.get_if_block_depth() > 0 && !need_single_line(ctx.get_language()))
         {
             // missing endif directive(s)
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 missing_matching_endif, "", act_pos);
         }
     }
     else {
         act_token = eof;            // this is the last token
     }
 
 //  whitespace.shift_tokens(T_EOF);     // whitespace controller
     return act_token;                   // return eof token
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  emit_line_directive(): emits a line directive from the act_token data
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::emit_line_directive()
 {
     using namespace boost::wave;
 
     typename ContextT::position_type pos = act_token.get_position();
 
 //     if (must_emit_line_directive &&
 //         iter_ctx->emitted_lines+1 == act_pos.get_line() &&
 //         iter_ctx->filename == act_pos.get_file())
 //     {
 //         must_emit_line_directive = false;
 //         return false;
 //     }
 
     if (must_emit_line_directive ||
         iter_ctx->emitted_lines+1 != act_pos.get_line())
     {
         // unput the current token
         pending_queue.push_front(act_token);
         pos.set_line(act_pos.get_line());
 
         if (iter_ctx->emitted_lines+2 == act_pos.get_line() && act_pos.get_line() != 1) {
             // prefer to output a single newline instead of the #line directive
 //             whitespace.shift_tokens(T_NEWLINE);
             act_token = result_type(T_NEWLINE, "\n", pos);
         }
         else {
             // account for the newline emitted here
             act_pos.set_line(act_pos.get_line()-1);
             iter_ctx->emitted_lines = act_pos.get_line()-1;
 
             token_sequence_type pending;
 
             if (!ctx.get_hooks().emit_line_directive(ctx, pending, act_token))
             {
                 unsigned int column = 6;
 
                 // the hook did not generate anything, emit default #line
                 pos.set_column(1);
                 pending.push_back(result_type(T_PP_LINE, "#line", pos));
 
                 pos.set_column(column);      // account for '#line'
                 pending.push_back(result_type(T_SPACE, " ", pos));
 
                 // 21 is the max required size for a 64 bit integer represented as a
                 // string
 
                 std::string buffer = lexical_cast<std::string>(pos.get_line());
 
                 pos.set_column(++column);                 // account for ' '
                 pending.push_back(result_type(T_INTLIT, buffer.c_str(), pos));
                 pos.set_column(column += (unsigned int)buffer.size()); // account for <number>
                 pending.push_back(result_type(T_SPACE, " ", pos));
                 pos.set_column(++column);                 // account for ' '
 
                 std::string file("\"");
                 boost::filesystem::path filename(
                     wave::util::create_path(act_pos.get_file().c_str()));
 
                 using wave::util::impl::escape_lit;
                 file += escape_lit(wave::util::native_file_string(filename)) + "\"";
 
                 pending.push_back(result_type(T_STRINGLIT, file.c_str(), pos));
                 pos.set_column(column += (unsigned int)file.size());    // account for filename
                 pending.push_back(result_type(T_GENERATEDNEWLINE, "\n", pos));
             }
 
             // if there is some replacement text, insert it into the pending queue
             if (!pending.empty()) {
                 pending_queue.splice(pending_queue.begin(), pending);
                 act_token = pending_queue.front();
                 pending_queue.pop_front();
             }
         }
 
         must_emit_line_directive = false;     // we are now in sync
         return true;
     }
 
     must_emit_line_directive = false;         // we are now in sync
     return false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  pptoken(): return the next preprocessed token
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline typename pp_iterator_functor<ContextT>::result_type const &
 pp_iterator_functor<ContextT>::pp_token()
 {
     using namespace boost::wave;
 
     token_id id = token_id(*iter_ctx->first);
 
     // eat all T_PLACEHOLDER tokens, eventually slipped through out of the
     // macro engine
     do {
         if (!pending_queue.empty()) {
             // if there are pending tokens in the queue, return the first one
             act_token = pending_queue.front();
             pending_queue.pop_front();
             act_pos = act_token.get_position();
         }
         else if (!unput_queue.empty()
               || T_IDENTIFIER == id
               || IS_CATEGORY(id, KeywordTokenType)
               || IS_EXTCATEGORY(id, OperatorTokenType|AltExtTokenType)
               || IS_CATEGORY(id, BoolLiteralTokenType))
         {
             //  call the lexer, preprocess the required number of tokens, put them
             //  into the unput queue
             act_token = ctx.expand_tokensequence(iter_ctx->first,
                 iter_ctx->last, pending_queue, unput_queue, skipped_newline);
         }
         else {
             // simply return the next token
             act_token = *iter_ctx->first;
             ++iter_ctx->first;
         }
         id = token_id(act_token);
 
     } while (T_PLACEHOLDER == id);
     return act_token;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  pp_directive(): recognize a preprocessor directive
 //
 ///////////////////////////////////////////////////////////////////////////////
 namespace impl {
 
     // call 'found_directive' preprocessing hook
     template <typename ContextT>
     bool call_found_directive_hook(ContextT& ctx,
         typename ContextT::token_type const& found_directive)
     {
         if (ctx.get_hooks().found_directive(ctx.derived(), found_directive))
             return true;    // skip this directive and return newline only
         return false;
     }
 
 //     // call 'skipped_token' preprocessing hook
 //     template <typename ContextT>
 //     void call_skipped_token_hook(ContextT& ctx,
 //         typename ContextT::token_type const& skipped)
 //     {
 //         ctx.get_hooks().skipped_token(ctx.derived(), skipped);
 //     }
 
     template <typename ContextT, typename IteratorT>
     bool next_token_is_pp_directive(ContextT &ctx, IteratorT &it, IteratorT const &end)
     {
         using namespace boost::wave;
 
         token_id id = T_UNKNOWN;
         for (/**/; it != end; ++it) {
             id = token_id(*it);
             if (!IS_CATEGORY(id, WhiteSpaceTokenType))
                 break;          // skip leading whitespace
             if (IS_CATEGORY(id, EOLTokenType) || IS_CATEGORY(id, EOFTokenType))
                 break;          // do not enter a new line
             if (T_CPPCOMMENT == id ||
                 context_policies::util::ccomment_has_newline(*it))
             {
                 break;
             }
 
             // this token gets skipped
             util::impl::call_skipped_token_hook(ctx, *it);
         }
         BOOST_ASSERT(it == end || id != T_UNKNOWN);
         return it != end && IS_CATEGORY(id, PPTokenType);
     }
 
     // verify that there isn't anything significant left on the line
     template <typename ContextT, typename IteratorT>
     bool pp_is_last_on_line(ContextT &ctx, IteratorT &it, IteratorT const &end,
         bool call_hook = true)
     {
         using namespace boost::wave;
 
         // this token gets skipped
         if (call_hook)
             util::impl::call_skipped_token_hook(ctx, *it);
 
         for (++it; it != end; ++it) {
             token_id id = token_id(*it);
 
             if (T_CPPCOMMENT == id || T_NEWLINE == id ||
                 context_policies::util::ccomment_has_newline(*it))
             {
                 if (call_hook)
                     util::impl::call_skipped_token_hook(ctx, *it);
                 ++it;           // skip eol/C/C++ comment
                 return true;    // no more significant tokens on this line
             }
 
             if (!IS_CATEGORY(id, WhiteSpaceTokenType))
                 break;
 
             // this token gets skipped
             if (call_hook)
                 util::impl::call_skipped_token_hook(ctx, *it);
         }
         return need_no_newline_at_end_of_file(ctx.get_language()) &&
             ((it == end) || (T_EOF == token_id(*it)));
     }
 
     ///////////////////////////////////////////////////////////////////////////
     template <typename ContextT, typename IteratorT>
     bool skip_to_eol(ContextT &ctx, IteratorT &it, IteratorT const &end,
         bool call_hook = true)
     {
         using namespace boost::wave;
 
         for (/**/; it != end; ++it) {
         token_id id = token_id(*it);
 
             if (T_CPPCOMMENT == id || T_NEWLINE == id ||
                 context_policies::util::ccomment_has_newline(*it))
             {
                 // always call hook for eol
                 util::impl::call_skipped_token_hook(ctx, *it);
                 ++it;           // skip eol/C/C++ comment
                 return true;    // found eol
             }
 
             if (call_hook)
                 util::impl::call_skipped_token_hook(ctx, *it);
         }
         return false;
     }
 
     ///////////////////////////////////////////////////////////////////////////
     template <typename ContextT, typename ContainerT>
     inline void
     remove_leading_whitespace(ContextT &ctx, ContainerT& c, bool call_hook = true)
     {
         typename ContainerT::iterator it = c.begin();
         while (IS_CATEGORY(*it, WhiteSpaceTokenType)) {
             typename ContainerT::iterator save = it++;
             if (call_hook)
                 util::impl::call_skipped_token_hook(ctx, *save);
             c.erase(save);
         }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 template <typename IteratorT>
 inline bool
 pp_iterator_functor<ContextT>::extract_identifier(IteratorT &it)
 {
     token_id id = util::impl::skip_whitespace(it, iter_ctx->last);
     if (T_IDENTIFIER == id || IS_CATEGORY(id, KeywordTokenType) ||
         IS_EXTCATEGORY(id, OperatorTokenType|AltExtTokenType) ||
         IS_CATEGORY(id, BoolLiteralTokenType))
     {
         IteratorT save = it;
         if (impl::pp_is_last_on_line(ctx, save, iter_ctx->last, false))
             return true;
     }
 
     // report the ill formed directive
     impl::skip_to_eol(ctx, it, iter_ctx->last);
 
     string_type str(util::impl::as_string<string_type>(iter_ctx->first, it));
 
     seen_newline = true;
     iter_ctx->first = it;
     on_illformed(str);
     return false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 template <typename IteratorT>
 inline bool
 pp_iterator_functor<ContextT>::ensure_is_last_on_line(IteratorT& it, bool call_hook)
 {
     if (!impl::pp_is_last_on_line(ctx, it, iter_ctx->last, call_hook))
     {
         // enable error recovery (start over with the next line)
         impl::skip_to_eol(ctx, it, iter_ctx->last);
 
         string_type str(util::impl::as_string<string_type>(iter_ctx->first, it));
 
         seen_newline = true;
         iter_ctx->first = it;
 
         // report an invalid directive
         on_illformed(str);
         return false;
     }
 
     if (it == iter_ctx->last && !need_single_line(ctx.get_language()))
     {
         // The line doesn't end with an eol but eof token.
         seen_newline = true;    // allow to resume after warning
         iter_ctx->first = it;
 
         if (!need_no_newline_at_end_of_file(ctx.get_language()))
         {
             // Trigger a warning that the last line was not terminated with a
             // newline.
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 last_line_not_terminated, "", act_pos);
         }
 
         return false;
     }
     return true;
 }
 
 template <typename ContextT>
 template <typename IteratorT>
 inline bool
 pp_iterator_functor<ContextT>::skip_to_eol_with_check(IteratorT &it, bool call_hook)
 {
     typename ContextT::string_type value ((*it).get_value());
     if (!impl::skip_to_eol(ctx, it, iter_ctx->last, call_hook) &&
         !need_single_line(ctx.get_language()))
     {
         // The line doesn't end with an eol but eof token.
         seen_newline = true;    // allow to resume after warning
         iter_ctx->first = it;
 
         if (!need_no_newline_at_end_of_file(ctx.get_language()))
         {
             // Trigger a warning, that the last line was not terminated with a
             // newline.
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 last_line_not_terminated, "", act_pos);
         }
         return false;
     }
 
     // normal line ending reached, adjust iterator and flag
     seen_newline = true;
     iter_ctx->first = it;
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //  handle_pp_directive: handle certain pp_directives
 template <typename ContextT>
 template <typename IteratorT>
 inline bool
 pp_iterator_functor<ContextT>::handle_pp_directive(IteratorT &it)
 {
     token_id id = token_id(*it);
     bool can_exit = true;
     bool call_hook_in_skip = true;
     if (!ctx.get_if_block_status()) {
         if (IS_EXTCATEGORY(*it, PPConditionalTokenType)) {
             // simulate the if block hierarchy
             switch (id) {
             case T_PP_IFDEF:        // #ifdef
             case T_PP_IFNDEF:       // #ifndef
             case T_PP_IF:           // #if
                 ctx.enter_if_block(false);
                 break;
 
             case T_PP_ELIF:         // #elif
                 if (!ctx.get_enclosing_if_block_status()) {
                     if (!ctx.enter_elif_block(false)) {
                         // #else without matching #if
                         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                             missing_matching_if, "#elif", act_pos);
                         return true;  // do not analyze this directive any further
                     }
                 }
                 else {
                     can_exit = false;   // #elif is not always safe to skip
                 }
                 break;
 
             case T_PP_ELSE:         // #else
             case T_PP_ENDIF:        // #endif
                 {
                 // handle this directive
                     if (T_PP_ELSE == token_id(*it))
                         on_else();
                     else
                         on_endif();
 
                 // make sure, there are no (non-whitespace) tokens left on
                 // this line
                     ensure_is_last_on_line(it);
 
                 // we skipped to the end of this line already
                     seen_newline = true;
                     iter_ctx->first = it;
                 }
                 if (T_PP_ENDIF == id)
                     must_emit_line_directive = true;
                 return true;
 
             default:                // #something else
                 on_illformed((*it).get_value());
                 break;
             }
         }
         else {
             util::impl::call_skipped_token_hook(ctx, *it);
             ++it;
         }
     }
     else {
         // try to handle the simple pp directives without parsing
         result_type directive = *it;
         bool include_next = false;
         switch (id) {
         case T_PP_QHEADER:        // #include "..."
 #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
         case T_PP_QHEADER_NEXT:
 #endif
             include_next = (T_PP_QHEADER_NEXT == id) ? true : false;
             if (!impl::call_found_directive_hook(ctx, *it))
             {
                 string_type dir((*it).get_value());
 
                 // make sure, there are no (non-whitespace) tokens left on
                 // this line
                 if (ensure_is_last_on_line(it))
                 {
                     seen_newline = true;
                     iter_ctx->first = it;
                     on_include (dir, false, include_next);
                 }
                 return true;
             }
             break;
 
         case T_PP_HHEADER:        // #include <...>
 #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
         case T_PP_HHEADER_NEXT:
 #endif
             include_next = (T_PP_HHEADER_NEXT == id) ? true : false;
             if (!impl::call_found_directive_hook(ctx, *it))
             {
                 string_type dir((*it).get_value());
 
                 // make sure, there are no (non-whitespace) tokens left on
                 // this line
                 if (ensure_is_last_on_line(it))
                 {
                     seen_newline = true;
                     iter_ctx->first = it;
                     on_include (dir, true, include_next);
                 }
                 return true;
             }
             break;
 
         case T_PP_ELSE:         // #else
         case T_PP_ENDIF:        // #endif
             if (!impl::call_found_directive_hook(ctx, *it))
             {
                 // handle this directive
                 if (T_PP_ELSE == token_id(*it))
                     on_else();
                 else
                     on_endif();
 
                 // make sure, there are no (non-whitespace) tokens left on
                 // this line
                 ensure_is_last_on_line(it);
 
                 // we skipped to the end of this line already
                 seen_newline = true;
                 iter_ctx->first = it;
                 if (T_PP_ENDIF == id)
                     must_emit_line_directive = true;
                 return true;
             }
             break;
 
             // extract everything on this line as arguments
 //         case T_PP_IF:                   // #if
 //         case T_PP_ELIF:                 // #elif
 //         case T_PP_ERROR:                // #error
 //         case T_PP_WARNING:              // #warning
 //         case T_PP_PRAGMA:               // #pragma
 //         case T_PP_LINE:                 // #line
 //             break;
 
         // extract first non-whitespace token as argument
         case T_PP_UNDEF:                // #undef
             if (!impl::call_found_directive_hook(ctx, *it) &&
                 extract_identifier(it))
             {
                 on_undefine(it);
             }
             call_hook_in_skip = false;
             break;
 
 #if BOOST_WAVE_SUPPORT_MS_EXTENSIONS != 0
 //         case T_MSEXT_PP_REGION:         // #region ...
 //             break;
 //
 //         case T_MSEXT_PP_ENDREGION:      // #endregion
 //             break;
 #endif
 
         default:
             can_exit = false;
             break;
         }
     }
 
     // start over with the next line, if only possible
     if (can_exit) {
         skip_to_eol_with_check(it, call_hook_in_skip);
         return true;    // may be safely ignored
     }
     return false;   // do not ignore this pp directive
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //  pp_directive(): recognize a preprocessor directive
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::pp_directive()
 {
     using namespace cpplexer;
 
     // test, if the next non-whitespace token is a pp directive
     lexer_type it = iter_ctx->first;
 
     if (!impl::next_token_is_pp_directive(ctx, it, iter_ctx->last)) {
         // skip null pp directive (no need to do it via the parser)
         if (it != iter_ctx->last && T_POUND == BASE_TOKEN(token_id(*it))) {
             if (impl::pp_is_last_on_line(ctx, it, iter_ctx->last)) {
                 // start over with the next line
                 seen_newline = true;
                 iter_ctx->first = it;
                 return true;
             }
             else if (ctx.get_if_block_status()) {
                 // report invalid pp directive
                 impl::skip_to_eol(ctx, it, iter_ctx->last);
                 seen_newline = true;
 
                 string_type str(boost::wave::util::impl::as_string<string_type>(
                     iter_ctx->first, it));
 
                 token_sequence_type faulty_line;
 
                 for (/**/; iter_ctx->first != it; ++iter_ctx->first)
                     faulty_line.push_back(*iter_ctx->first);
 
                 token_sequence_type pending;
                 if (ctx.get_hooks().found_unknown_directive(ctx, faulty_line, pending))
                 {
                     // if there is some replacement text, insert it into the pending queue
                     if (!pending.empty())
                         pending_queue.splice(pending_queue.begin(), pending);
                     return true;
                 }
 
                 // default behavior is to throw an exception
                 on_illformed(str);
             }
         }
 
         // this line does not contain a pp directive, so simply return
         return false;
     }
 
     // found eof
     if (it == iter_ctx->last)
         return false;
 
     // ignore/handle all pp directives not related to conditional compilation while
     // if block status is false
     if (handle_pp_directive(it)) {
         // we may skip pp directives only if the current if block status is
         // false or if it was a #include directive we could handle directly
         return true;    //  the pp directive has been handled/skipped
     }
 
     // found a pp directive, so try to identify it, start with the pp_token
     bool found_eof = false;
     result_type found_directive;
     token_sequence_type found_eoltokens;
 
     tree_parse_info_type hit = cpp_grammar_type::parse_cpp_grammar(
         it, iter_ctx->last, act_pos, found_eof, found_directive, found_eoltokens);
 
     if (hit.match) {
         // position the iterator past the matched sequence to allow
         // resynchronization, if an error occurs
         iter_ctx->first = hit.stop;
         seen_newline = true;
         must_emit_line_directive = true;
 
         // found a valid pp directive, dispatch to the correct function to handle
         // the found pp directive
         bool result = dispatch_directive(hit, found_directive, found_eoltokens);
 
         if (found_eof && !need_single_line(ctx.get_language()) &&
             !need_no_newline_at_end_of_file(ctx.get_language()))
         {
             // The line was terminated with an end of file token.
             // So trigger a warning, that the last line was not terminated with a
             // newline.
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 last_line_not_terminated, "", act_pos);
         }
         return result;
     }
     else if (token_id(found_directive) != T_EOF) {
         // recognized invalid directive
         impl::skip_to_eol(ctx, it, iter_ctx->last);
         seen_newline = true;
 
         string_type str(boost::wave::util::impl::as_string<string_type>(
             iter_ctx->first, it));
         iter_ctx->first = it;
 
         // report the ill formed directive
         on_illformed(str);
     }
     return false;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  dispatch_directive(): dispatch a recognized preprocessor directive
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::dispatch_directive(
     tree_parse_info_type const &hit, result_type const& found_directive,
     token_sequence_type const& found_eoltokens)
 {
     using namespace cpplexer;
 
     typedef typename parse_tree_type::const_iterator const_child_iterator_t;
 
     // this iterator points to the root node of the parse tree
     const_child_iterator_t begin = hit.trees.begin();
 
     // decide, which preprocessor directive was found
     parse_tree_type const& root = (*begin).children;
     parse_node_value_type const& nodeval = get_first_leaf(*root.begin()).value;
     //long node_id = nodeval.id().to_long();
 
     const_child_iterator_t begin_child_it = (*root.begin()).children.begin();
     const_child_iterator_t end_child_it = (*root.begin()).children.end();
 
     token_id id = token_id(found_directive);
 
     // call preprocessing hook
     if (impl::call_found_directive_hook(ctx, found_directive))
         return true;    // skip this directive and return newline only
 
     switch (id) {
 //     case T_PP_QHEADER:      // #include "..."
 // #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
 //     case T_PP_QHEADER_NEXT: // #include_next "..."
 // #endif
 //         on_include ((*nodeval.begin()).get_value(), false,
 //             T_PP_QHEADER_NEXT == id);
 //         break;
 
 //     case T_PP_HHEADER:      // #include <...>
 // #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
 //     case T_PP_HHEADER_NEXT: // #include_next <...>
 // #endif
 //         on_include ((*nodeval.begin()).get_value(), true,
 //             T_PP_HHEADER_NEXT == id);
 //         break;
 
     case T_PP_INCLUDE:      // #include ...
 #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
     case T_PP_INCLUDE_NEXT: // #include_next ...
 #endif
         on_include (begin_child_it, end_child_it, T_PP_INCLUDE_NEXT == id);
         break;
 
     case T_PP_DEFINE:       // #define
         on_define (*begin);
         break;
 
 //     case T_PP_UNDEF:        // #undef
 //         on_undefine(*nodeval.begin());
 //         break;
 //
     case T_PP_IFDEF:        // #ifdef
         on_ifdef(found_directive, begin_child_it, end_child_it);
         break;
 
     case T_PP_IFNDEF:       // #ifndef
         on_ifndef(found_directive, begin_child_it, end_child_it);
         break;
 
     case T_PP_IF:           // #if
         on_if(found_directive, begin_child_it, end_child_it);
         break;
 
     case T_PP_ELIF:         // #elif
         on_elif(found_directive, begin_child_it, end_child_it);
         break;
 
 //     case T_PP_ELSE:         // #else
 //         on_else();
 //         break;
 
 //     case T_PP_ENDIF:        // #endif
 //         on_endif();
 //         break;
 
     case T_PP_LINE:         // #line
         on_line(begin_child_it, end_child_it);
         break;
 
     case T_PP_ERROR:        // #error
         on_error(begin_child_it, end_child_it);
         break;
 
 #if BOOST_WAVE_SUPPORT_WARNING_DIRECTIVE != 0
     case T_PP_WARNING:      // #warning
         on_warning(begin_child_it, end_child_it);
         break;
 #endif
 
     case T_PP_PRAGMA:       // #pragma
         return on_pragma(begin_child_it, end_child_it);
 
 #if BOOST_WAVE_SUPPORT_MS_EXTENSIONS != 0
     case T_MSEXT_PP_REGION:
     case T_MSEXT_PP_ENDREGION:
         break;              // ignore these
 #endif
 
     default:                // #something else
         on_illformed((*nodeval.begin()).get_value());
 
         // if we end up here, we have been instructed to ignore the error, so
         // we simply copy the whole construct to the output
         {
             token_sequence_type expanded;
             get_token_value<result_type, parse_node_type> get_value;
 
             std::copy(make_ref_transform_iterator(begin_child_it, get_value),
                 make_ref_transform_iterator(end_child_it, get_value),
                 std::inserter(expanded, expanded.end()));
             pending_queue.splice(pending_queue.begin(), expanded);
         }
         break;
     }
 
     // properly skip trailing newline for all directives
     typename token_sequence_type::const_iterator eol = found_eoltokens.begin();
     impl::skip_to_eol(ctx, eol, found_eoltokens.end());
     return true;    // return newline only
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_include: handle #include <...> or #include "..." directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_include (string_type const &s,
     bool is_system, bool include_next)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
 // strip quotes first, extract filename
 typename string_type::size_type pos_end = s.find_last_of(is_system ? '>' : '\"');
 
     if (string_type::npos == pos_end) {
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_include_statement,
             s.c_str(), act_pos);
         return;
     }
 
 typename string_type::size_type pos_begin =
     s.find_last_of(is_system ? '<' : '\"', pos_end-1);
 
     if (string_type::npos == pos_begin) {
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_include_statement,
             s.c_str(), act_pos);
         return;
     }
 
     std::string file_token(s.substr(pos_begin, pos_end - pos_begin + 1).c_str());
     std::string file_path(s.substr(pos_begin + 1, pos_end - pos_begin - 1).c_str());
 
     // finally include the file
     on_include_helper(file_token.c_str(), file_path.c_str(), is_system,
         include_next);
 }
 
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::on_include_helper(char const* f, char const* s,
     bool is_system, bool include_next)
 {
     namespace fs = boost::filesystem;
 
     // try to locate the given file, searching through the include path lists
     std::string file_path(s);
     std::string dir_path;
 #if BOOST_WAVE_SUPPORT_INCLUDE_NEXT != 0
     char const* current_name = include_next ? iter_ctx->real_filename.c_str() : 0;
 #else
     char const* current_name = 0; // never try to match current file name
 #endif
 
 // call the 'found_include_directive' hook function
     if (ctx.get_hooks().found_include_directive(ctx.derived(), f, include_next))
         return true;    // client returned false: skip file to include
 
     file_path = util::impl::unescape_lit(file_path);
     std::string native_path_str;
 
     if (!ctx.get_hooks().locate_include_file(ctx, file_path, is_system,
             current_name, dir_path, native_path_str))
     {
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_include_file,
             file_path.c_str(), act_pos);
         return false;
     }
 
 // test, if this file is known through a #pragma once directive
 #if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
     if (!ctx.has_pragma_once(native_path_str))
 #endif
     {
         // the new include file determines the actual current directory
         ctx.set_current_directory(native_path_str.c_str());
 
         // preprocess the opened file
         boost::shared_ptr<base_iteration_context_type> new_iter_ctx(
             new iteration_context_type(ctx, native_path_str.c_str(), act_pos,
                 boost::wave::enable_prefer_pp_numbers(ctx.get_language()),
                 is_system ? base_iteration_context_type::system_header :
                             base_iteration_context_type::user_header));
 
         // call the include policy trace function
         ctx.get_hooks().opened_include_file(ctx.derived(), dir_path, file_path,
             is_system);
 
         // store current file position
         iter_ctx->real_relative_filename = ctx.get_current_relative_filename().c_str();
         iter_ctx->filename = act_pos.get_file();
         iter_ctx->line = act_pos.get_line();
         iter_ctx->if_block_depth = ctx.get_if_block_depth();
         iter_ctx->emitted_lines = (unsigned int)(-1);   // force #line directive
 
         // push the old iteration context onto the stack and continue with the new
         ctx.push_iteration_context(act_pos, iter_ctx);
         iter_ctx = new_iter_ctx;
         seen_newline = true;        // fake a newline to trigger pp_directive
         must_emit_line_directive = true;
 
         act_pos.set_file(iter_ctx->filename);  // initialize file position
 #if BOOST_WAVE_SUPPORT_PRAGMA_ONCE != 0
         fs::path rfp(wave::util::create_path(iter_ctx->real_filename.c_str()));
         std::string real_filename(rfp.string());
         ctx.set_current_filename(real_filename.c_str());
 #endif
 
         ctx.set_current_relative_filename(dir_path.c_str());
         iter_ctx->real_relative_filename = dir_path.c_str();
 
         act_pos.set_line(iter_ctx->line);
         act_pos.set_column(0);
     }
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_include(): handle #include ... directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_include(
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end, bool include_next)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // preprocess the given token sequence (the body of the #include directive)
     get_token_value<result_type, parse_node_type> get_value;
     token_sequence_type expanded;
     token_sequence_type toexpand;
 
     std::copy(make_ref_transform_iterator(begin, get_value),
         make_ref_transform_iterator(end, get_value),
         std::inserter(toexpand, toexpand.end()));
 
     typename token_sequence_type::iterator begin2 = toexpand.begin();
     // expanding the computed include
     ctx.expand_whole_tokensequence(begin2, toexpand.end(), expanded,
                                    false, false);
 
     // now, include the file
     using namespace boost::wave::util::impl;
     string_type s (trim_whitespace(as_string(expanded)));
     bool is_system = '<' == s[0] && '>' == s[s.size()-1];
 
     if (!is_system && !('\"' == s[0] && '\"' == s[s.size()-1])) {
     // should resolve into something like <...> or "..."
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, bad_include_statement,
             s.c_str(), act_pos);
         return;
     }
     on_include(s, is_system, include_next);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_define(): handle #define directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_define (parse_node_type const &node)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // retrieve the macro definition from the parse tree
     result_type macroname;
     std::vector<result_type> macroparameters;
     token_sequence_type macrodefinition;
     bool has_parameters = false;
     position_type pos(act_token.get_position());
 
     if (!boost::wave::util::retrieve_macroname(ctx, node,
             BOOST_WAVE_PLAIN_DEFINE_ID, macroname, pos, false))
         return;
     has_parameters = boost::wave::util::retrieve_macrodefinition(node,
         BOOST_WAVE_MACRO_PARAMETERS_ID, macroparameters, pos, false);
     boost::wave::util::retrieve_macrodefinition(node,
         BOOST_WAVE_MACRO_DEFINITION_ID, macrodefinition, pos, false);
 
     if (has_parameters) {
 #if BOOST_WAVE_SUPPORT_VARIADICS_PLACEMARKERS != 0
         if (boost::wave::need_variadics(ctx.get_language())) {
             // test whether ellipsis are given, and if yes, if these are placed as the
             // last argument, test if __VA_ARGS__ is used as a macro parameter name
             using namespace cpplexer;
             typedef typename std::vector<result_type>::iterator
                 parameter_iterator_t;
 
             bool seen_ellipses = false;
             parameter_iterator_t end = macroparameters.end();
             for (parameter_iterator_t pit = macroparameters.begin();
                 pit != end; ++pit)
             {
                 if (seen_ellipses) {
                     // ellipses are not the last given formal argument
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement, macroname.get_value().c_str(),
                         (*pit).get_position());
                     return;
                 }
                 if (T_ELLIPSIS == token_id(*pit))
                     seen_ellipses = true;
 
                 // can't use __VA_ARGS__ as a argument name
                 if ("__VA_ARGS__" == (*pit).get_value()) {
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement_va_args,
                         macroname.get_value().c_str(), (*pit).get_position());
                     return;
                 }
 
 #if BOOST_WAVE_SUPPORT_VA_OPT != 0
                 // can't use __VA_OPT__ either
                 if (boost::wave::need_va_opt(ctx.get_language()) &&
                     ("__VA_OPT__" == (*pit).get_value())) {
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement_va_opt,
                         macroname.get_value().c_str(), (*pit).get_position());
                     return;
                 }
 #endif
             }
 
             // if there wasn't an ellipsis, then there shouldn't be a __VA_ARGS__
             // placeholder in the definition too [C99 Standard 6.10.3.5]
             if (!seen_ellipses) {
                 typedef typename token_sequence_type::iterator definition_iterator_t;
 
                 bool seen_va_args = false;
 #if BOOST_WAVE_SUPPORT_VA_OPT != 0
                 bool seen_va_opt = false;
 #endif
                 definition_iterator_t pend = macrodefinition.end();
                 for (definition_iterator_t dit = macrodefinition.begin();
                      dit != pend; ++dit)
                 {
                     if (T_IDENTIFIER == token_id(*dit) &&
                         "__VA_ARGS__" == (*dit).get_value())
                     {
                         seen_va_args = true;
                     }
 #if BOOST_WAVE_SUPPORT_VA_OPT != 0
                     if (T_IDENTIFIER == token_id(*dit) &&
                         "__VA_OPT__" == (*dit).get_value())
                     {
                         seen_va_opt = true;
                     }
 #endif
                 }
                 if (seen_va_args) {
                     // must not have seen __VA_ARGS__ placeholder
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement_va_args,
                         macroname.get_value().c_str(), act_token.get_position());
                     return;
                 }
 #if BOOST_WAVE_SUPPORT_VA_OPT != 0
                 if (seen_va_opt) {
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement_va_opt,
                         macroname.get_value().c_str(), act_token.get_position());
                     return;
                 }
 #endif
             }
         }
         else
 #endif // BOOST_WAVE_SUPPORT_VARIADICS_PLACEMARKERS != 0
         {
             // test, that there is no T_ELLIPSES given
             using namespace cpplexer;
             typedef typename std::vector<result_type>::iterator
                 parameter_iterator_t;
 
             parameter_iterator_t end = macroparameters.end();
             for (parameter_iterator_t pit = macroparameters.begin();
                 pit != end; ++pit)
             {
                 if (T_ELLIPSIS == token_id(*pit)) {
                     // if variadics are disabled, no ellipses should be given
                     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                         bad_define_statement, macroname.get_value().c_str(),
                         (*pit).get_position());
                     return;
                 }
             }
         }
     }
 
     // add the new macro to the macromap
     ctx.add_macro_definition(macroname, has_parameters, macroparameters,
         macrodefinition);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_undefine(): handle #undef directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_undefine (lexer_type const &it)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // retrieve the macro name to undefine from the parse tree
     ctx.remove_macro_definition((*it).get_value()); // throws for predefined macros
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_ifdef(): handle #ifdef directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_ifdef(
     result_type const& found_directive,
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     get_token_value<result_type, parse_node_type> get_value;
     token_sequence_type toexpand;
 
     std::copy(make_ref_transform_iterator((*begin).children.begin(), get_value),
               make_ref_transform_iterator((*begin).children.end(), get_value),
               std::inserter(toexpand, toexpand.end()));
 
     bool is_defined = false;
 
     do {
         is_defined = ctx.is_defined_macro(toexpand.begin(), toexpand.end());
     } while (ctx.get_hooks().evaluated_conditional_expression(ctx.derived(),
              found_directive, toexpand, is_defined));
     ctx.enter_if_block(is_defined);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_ifndef(): handle #ifndef directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_ifndef(
     result_type const& found_directive,
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     get_token_value<result_type, parse_node_type> get_value;
     token_sequence_type toexpand;
 
     std::copy(make_ref_transform_iterator((*begin).children.begin(), get_value),
               make_ref_transform_iterator((*begin).children.end(), get_value),
               std::inserter(toexpand, toexpand.end()));
 
     bool is_defined = false;
 
     do {
         is_defined = ctx.is_defined_macro(toexpand.begin(), toexpand.end());
     } while (ctx.get_hooks().evaluated_conditional_expression(ctx.derived(),
              found_directive, toexpand, is_defined));
     ctx.enter_if_block(!is_defined);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_else(): handle #else directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_else()
 {
     if (!ctx.enter_else_block()) {
         // #else without matching #if
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, missing_matching_if,
             "#else", act_pos);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_endif(): handle #endif directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_endif()
 {
     if (!ctx.exit_if_block()) {
         // #endif without matching #if
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, missing_matching_if,
             "#endif", act_pos);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //  replace all remaining (== undefined) identifiers with an integer literal '0'
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::replace_undefined_identifiers(
     token_sequence_type &expanded)
 {
     typename token_sequence_type::iterator exp_end = expanded.end();
     for (typename token_sequence_type::iterator exp_it = expanded.begin();
          exp_it != exp_end; ++exp_it)
     {
         using namespace boost::wave;
 
         token_id id = token_id(*exp_it);
         if (IS_CATEGORY(id, IdentifierTokenType) ||
             IS_CATEGORY(id, KeywordTokenType))
         {
             (*exp_it).set_token_id(T_INTLIT);
             (*exp_it).set_value("0");
         }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_if(): handle #if directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_if(
     result_type const& found_directive,
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     // preprocess the given sequence into the provided list
     get_token_value<result_type, parse_node_type> get_value;
     token_sequence_type toexpand;
 
     std::copy(make_ref_transform_iterator(begin, get_value),
         make_ref_transform_iterator(end, get_value),
         std::inserter(toexpand, toexpand.end()));
 
     impl::remove_leading_whitespace(ctx, toexpand);
 
     bool if_status = false;
     grammars::value_error status = grammars::error_noerror;
     token_sequence_type expanded;
 
     do {
         expanded.clear();
 
         typename token_sequence_type::iterator begin2 = toexpand.begin();
         ctx.expand_whole_tokensequence(begin2, toexpand.end(), expanded);
 
         // replace all remaining (== undefined) identifiers with an integer literal '0'
         replace_undefined_identifiers(expanded);
 
 #if BOOST_WAVE_DUMP_CONDITIONAL_EXPRESSIONS != 0
         {
             string_type outstr(boost::wave::util::impl::as_string(toexpand));
             outstr += "(" + boost::wave::util::impl::as_string(expanded) + ")";
             BOOST_WAVE_DUMP_CONDITIONAL_EXPRESSIONS_OUT << "#if " << outstr
                 << std::endl;
         }
 #endif
         try {
             // parse the expression and enter the #if block
             if_status = grammars::expression_grammar_gen<result_type>::
                     evaluate(expanded.begin(), expanded.end(), act_pos,
                         ctx.get_if_block_status(), status);
         }
         catch (boost::wave::preprocess_exception const& e) {
             // any errors occurred have to be dispatched to the context hooks
             ctx.get_hooks().throw_exception(ctx.derived(), e);
             break;
         }
 
     } while (ctx.get_hooks().evaluated_conditional_expression(ctx.derived(),
                 found_directive, toexpand, if_status)
              && status == grammars::error_noerror);
 
     ctx.enter_if_block(if_status);
     if (grammars::error_noerror != status) {
         // division or other error by zero occurred
         string_type expression = util::impl::as_string(expanded);
         if (0 == expression.size())
             expression = "<empty expression>";
 
         if (grammars::error_division_by_zero & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, division_by_zero,
                 expression.c_str(), act_pos);
         }
         else if (grammars::error_integer_overflow & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, integer_overflow,
                 expression.c_str(), act_pos);
         }
         else if (grammars::error_character_overflow & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 character_literal_out_of_range, expression.c_str(), act_pos);
         }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_elif(): handle #elif directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_elif(
     result_type const& found_directive,
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     // preprocess the given sequence into the provided list
     get_token_value<result_type, parse_node_type> get_value;
     token_sequence_type toexpand;
 
     std::copy(make_ref_transform_iterator(begin, get_value),
         make_ref_transform_iterator(end, get_value),
         std::inserter(toexpand, toexpand.end()));
 
     impl::remove_leading_whitespace(ctx, toexpand);
 
     // check current if block status
     if (ctx.get_if_block_some_part_status()) {
         if (!ctx.enter_elif_block(false)) {
             // #else without matching #if
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 missing_matching_if, "#elif", act_pos);
             // fall through...
         }
 
         // skip all the expression and the trailing whitespace
         typename token_sequence_type::iterator begin2 = toexpand.begin();
 
         impl::skip_to_eol(ctx, begin2, toexpand.end());
         return;     // one of previous #if/#elif was true, so don't enter this #elif
     }
 
     // preprocess the given sequence into the provided list
     bool if_status = false;
     grammars::value_error status = grammars::error_noerror;
     token_sequence_type expanded;
 
     do {
         expanded.clear();
 
         typename token_sequence_type::iterator begin2 = toexpand.begin();
         ctx.expand_whole_tokensequence(begin2, toexpand.end(), expanded);
 
         // replace all remaining (== undefined) identifiers with an integer literal '0'
         replace_undefined_identifiers(expanded);
 
 #if BOOST_WAVE_DUMP_CONDITIONAL_EXPRESSIONS != 0
         {
             string_type outstr(boost::wave::util::impl::as_string(toexpand));
             outstr += "(" + boost::wave::util::impl::as_string(expanded) + ")";
             BOOST_WAVE_DUMP_CONDITIONAL_EXPRESSIONS_OUT << "#elif " << outstr << std::endl;
         }
 #endif
 
         try {
             // parse the expression and enter the #elif block
             if_status = grammars::expression_grammar_gen<result_type>::
                 evaluate(expanded.begin(), expanded.end(), act_pos,
                     ctx.get_if_block_status(), status);
         }
         catch (boost::wave::preprocess_exception const& e) {
             // any errors occurred have to be dispatched to the context hooks
             ctx.get_hooks().throw_exception(ctx.derived(), e);
         }
 
     } while (ctx.get_hooks().evaluated_conditional_expression(ctx.derived(),
                 found_directive, toexpand, if_status)
              && status == grammars::error_noerror);
 
     if (!ctx.enter_elif_block(if_status)) {
         // #elif without matching #if
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, missing_matching_if,
             "#elif", act_pos);
         return;
     }
 
     if (grammars::error_noerror != status) {
         // division or other error by zero occurred
         string_type expression = util::impl::as_string(expanded);
         if (0 == expression.size())
             expression = "<empty expression>";
 
         if (grammars::error_division_by_zero & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, division_by_zero,
                 expression.c_str(), act_pos);
         }
         else if (grammars::error_integer_overflow & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 integer_overflow, expression.c_str(), act_pos);
         }
         else if (grammars::error_character_overflow & status) {
             BOOST_WAVE_THROW_CTX(ctx, preprocess_exception,
                 character_literal_out_of_range, expression.c_str(), act_pos);
         }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_illformed(): handles the illegal directive
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_illformed(
     typename result_type::string_type s)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // some messages have more than one newline at the end
     typename string_type::size_type p = s.find_last_not_of('\n');
     if (string_type::npos != p)
         s = s.substr(0, p+1);
 
     // throw the exception
     BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, ill_formed_directive,
         s.c_str(), act_pos);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_line(): handle #line directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 namespace impl {
 
     template <typename IteratorT, typename StringT>
     bool retrieve_line_info (IteratorT first, IteratorT const &last,
         unsigned int &line, StringT &file,
         boost::wave::preprocess_exception::error_code& error)
     {
         using namespace boost::wave;
         token_id id = token_id(*first);
         if (T_PP_NUMBER == id || T_INTLIT == id) {
         // extract line number
             using namespace std;    // some systems have atoi in namespace std
             line = (unsigned int)atoi((*first).get_value().c_str());
             if (0 == line)
                 error = preprocess_exception::bad_line_number;
 
         // re-extract line number with spirit to diagnose overflow
             using namespace boost::spirit::classic;
             if (!parse((*first).get_value().c_str(), int_p).full)
                 error = preprocess_exception::bad_line_number;
 
         // extract file name (if it is given)
             while (++first != last && IS_CATEGORY(*first, WhiteSpaceTokenType))
                 /**/;   // skip whitespace
 
             if (first != last) {
                 if (T_STRINGLIT != token_id(*first)) {
                     error = preprocess_exception::bad_line_filename;
                     return false;
                 }
 
                 StringT const& file_lit = (*first).get_value();
 
                 if ('L' == file_lit[0]) {
                     error = preprocess_exception::bad_line_filename;
                     return false;       // shouldn't be a wide character string
                 }
 
                 file = file_lit.substr(1, file_lit.size()-2);
 
             // test if there is other junk on this line
                 while (++first != last && IS_CATEGORY(*first, WhiteSpaceTokenType))
                     /**/;   // skip whitespace
             }
             return first == last;
         }
         error = preprocess_exception::bad_line_statement;
         return false;
     }
 }
 
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_line(
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // Try to extract the line number and file name from the given token list
     // directly. If that fails, preprocess the whole token sequence and try again
     // to extract this information.
     token_sequence_type expanded;
     get_token_value<result_type, parse_node_type> get_value;
 
     typedef typename ref_transform_iterator_generator<
             get_token_value<result_type, parse_node_type>,
             typename parse_tree_type::const_iterator
         >::type const_tree_iterator_t;
 
     const_tree_iterator_t first = make_ref_transform_iterator(begin, get_value);
     const_tree_iterator_t last = make_ref_transform_iterator(end, get_value);
 
     // try to interpret the #line body as a number followed by an optional
     // string literal
     unsigned int line = 0;
     preprocess_exception::error_code error = preprocess_exception::no_error;
     string_type file_name;
     token_sequence_type toexpand;
 
     std::copy(first, last, std::inserter(toexpand, toexpand.end()));
     if (!impl::retrieve_line_info(first, last, line, file_name, error)) {
         // preprocess the body of this #line message
         typename token_sequence_type::iterator begin2 = toexpand.begin();
         ctx.expand_whole_tokensequence(begin2, toexpand.end(),
                                        expanded, false, false);
 
         error = preprocess_exception::no_error;
         if (!impl::retrieve_line_info(expanded.begin(), expanded.end(),
             line, file_name, error))
         {
             typename ContextT::string_type msg(
                 boost::wave::util::impl::as_string(expanded));
             BOOST_WAVE_THROW_VAR_CTX(ctx, preprocess_exception, error,
                 msg.c_str(), act_pos);
             return;
         }
 
         // call the corresponding pp hook function
         ctx.get_hooks().found_line_directive(ctx.derived(), expanded, line,
             file_name.c_str());
     }
     else {
         // call the corresponding pp hook function
         ctx.get_hooks().found_line_directive(ctx.derived(), toexpand, line,
             file_name.c_str());
     }
 
     // the queues should be empty at this point
     BOOST_ASSERT(unput_queue.empty());
     BOOST_ASSERT(pending_queue.empty());
 
     // make sure error recovery starts on the next line
     must_emit_line_directive = true;
 
     // diagnose possible error in detected line directive
     if (error != preprocess_exception::no_error) {
         typename ContextT::string_type msg(
             boost::wave::util::impl::as_string(expanded));
         BOOST_WAVE_THROW_VAR_CTX(ctx, preprocess_exception, error,
             msg.c_str(), act_pos);
         return;
     }
 
     // set new line number/filename only if ok
     if (!file_name.empty()) {    // reuse current file name
         using boost::wave::util::impl::unescape_lit;
         act_pos.set_file(unescape_lit(file_name).c_str());
     }
     act_pos.set_line(line);
     if (iter_ctx->first != iter_ctx->last)
     {
       iter_ctx->first.set_position(act_pos);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_error(): handle #error directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_error(
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // preprocess the given sequence into the provided list
     token_sequence_type expanded;
     get_token_value<result_type, parse_node_type> get_value;
 
     typename ref_transform_iterator_generator<
         get_token_value<result_type, parse_node_type>,
         typename parse_tree_type::const_iterator
     >::type first = make_ref_transform_iterator(begin, get_value);
 
 #if BOOST_WAVE_PREPROCESS_ERROR_MESSAGE_BODY != 0
     // preprocess the body of this #error message
     token_sequence_type toexpand;
 
     std::copy(first, make_ref_transform_iterator(end, get_value),
         std::inserter(toexpand, toexpand.end()));
 
     typename token_sequence_type::iterator begin2 = toexpand.begin();
     ctx.expand_whole_tokensequence(begin2, toexpand.end(), expanded,
                                    false, false);
     if (!ctx.get_hooks().found_error_directive(ctx.derived(), toexpand))
 #else
     // simply copy the body of this #error message to the issued diagnostic
     // message
     std::copy(first, make_ref_transform_iterator(end, get_value),
         std::inserter(expanded, expanded.end()));
     if (!ctx.get_hooks().found_error_directive(ctx.derived(), expanded))
 #endif
     {
         // report the corresponding error
         BOOST_WAVE_STRINGTYPE msg(boost::wave::util::impl::as_string(expanded));
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, error_directive,
             msg.c_str(), act_pos);
     }
 }
 
 #if BOOST_WAVE_SUPPORT_WARNING_DIRECTIVE != 0
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_warning(): handle #warning directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline void
 pp_iterator_functor<ContextT>::on_warning(
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // preprocess the given sequence into the provided list
     token_sequence_type expanded;
     get_token_value<result_type, parse_node_type> get_value;
 
     typename ref_transform_iterator_generator<
         get_token_value<result_type, parse_node_type>,
         typename parse_tree_type::const_iterator
     >::type first = make_ref_transform_iterator(begin, get_value);
 
 #if BOOST_WAVE_PREPROCESS_ERROR_MESSAGE_BODY != 0
     // preprocess the body of this #warning message
     token_sequence_type toexpand;
 
     std::copy(first, make_ref_transform_iterator(end, get_value),
         std::inserter(toexpand, toexpand.end()));
 
     typename token_sequence_type::iterator begin2 = toexpand.begin();
     ctx.expand_whole_tokensequence(begin2, toexpand.end(), expanded,
                                    false, false);
     if (!ctx.get_hooks().found_warning_directive(ctx.derived(), toexpand))
 #else
     // simply copy the body of this #warning message to the issued diagnostic
     // message
     std::copy(first, make_ref_transform_iterator(end, get_value),
         std::inserter(expanded, expanded.end()));
     if (!ctx.get_hooks().found_warning_directive(ctx.derived(), expanded))
 #endif
     {
         // report the corresponding error
         BOOST_WAVE_STRINGTYPE msg(boost::wave::util::impl::as_string(expanded));
         BOOST_WAVE_THROW_CTX(ctx, preprocess_exception, warning_directive,
             msg.c_str(), act_pos);
     }
 }
 #endif // BOOST_WAVE_SUPPORT_WARNING_DIRECTIVE != 0
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  on_pragma(): handle #pragma directives
 //
 ///////////////////////////////////////////////////////////////////////////////
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::on_pragma(
     typename parse_tree_type::const_iterator const &begin,
     typename parse_tree_type::const_iterator const &end)
 {
     using namespace boost::wave;
 
     BOOST_ASSERT(ctx.get_if_block_status());
 
     // Look at the pragma token sequence and decide, if the first token is STDC
     // (see C99 standard [6.10.6.2]), if it is, the sequence must _not_ be
     // preprocessed.
     token_sequence_type expanded;
     get_token_value<result_type, parse_node_type> get_value;
 
     typedef typename ref_transform_iterator_generator<
             get_token_value<result_type, parse_node_type>,
             typename parse_tree_type::const_iterator
         >::type const_tree_iterator_t;
 
     const_tree_iterator_t first = make_ref_transform_iterator(begin, get_value);
     const_tree_iterator_t last = make_ref_transform_iterator(end, get_value);
 
     expanded.push_back(result_type(T_PP_PRAGMA, "#pragma", act_token.get_position()));
 
     while (first != last && IS_CATEGORY(*first, WhiteSpaceTokenType))
         expanded.push_back(*first++);   // skip whitespace
 
     if (first != last) {
         if (T_IDENTIFIER == token_id(*first) &&
             boost::wave::need_c99(ctx.get_language()) &&
             (*first).get_value() == "STDC")
         {
         // do _not_ preprocess the token sequence
             std::copy(first, last, std::inserter(expanded, expanded.end()));
         }
         else {
 #if BOOST_WAVE_PREPROCESS_PRAGMA_BODY != 0
             // preprocess the given tokensequence
             token_sequence_type toexpand;
 
             std::copy(first, last, std::inserter(toexpand, toexpand.end()));
 
             typename token_sequence_type::iterator begin2 = toexpand.begin();
             ctx.expand_whole_tokensequence(begin2, toexpand.end(),
                                            expanded, false, false);
 #else
             // do _not_ preprocess the token sequence
             std::copy(first, last, std::inserter(expanded, expanded.end()));
 #endif
         }
     }
 
     // the queues should be empty at this point
     BOOST_ASSERT(unput_queue.empty());
     BOOST_ASSERT(pending_queue.empty());
 
     // try to interpret the expanded #pragma body
     token_sequence_type pending;
     if (interpret_pragma(expanded, pending)) {
         // if there is some replacement text, insert it into the pending queue
         if (!pending.empty())
             pending_queue.splice(pending_queue.begin(), pending);
         return true;        // this #pragma was successfully recognized
     }
 
 #if BOOST_WAVE_EMIT_PRAGMA_DIRECTIVES != 0
     // Move the resulting token sequence into the pending_queue, so it will be
     // returned to the caller.
     if (boost::wave::need_emit_pragma_directives(ctx.get_language())) {
         pending_queue.splice(pending_queue.begin(), expanded);
         return false;       // return the whole #pragma directive
     }
 #endif
     return true;            // skip the #pragma at all
 }
 
 template <typename ContextT>
 inline bool
 pp_iterator_functor<ContextT>::interpret_pragma(
     token_sequence_type const &pragma_body, token_sequence_type &result)
 {
     using namespace cpplexer;
 
     typename token_sequence_type::const_iterator end = pragma_body.end();
     typename token_sequence_type::const_iterator it = pragma_body.begin();
     for (++it; it != end && IS_CATEGORY(*it, WhiteSpaceTokenType); ++it)
         /**/;   // skip whitespace
 
     if (it == end)      // eof reached
         return false;
 
     return boost::wave::util::interpret_pragma(
         ctx.derived(), act_token, it, end, result);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 }   // namespace impl
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 //  pp_iterator
 //
 //      The boost::wave::pp_iterator template is the iterator, through which
 //      the resulting preprocessed input stream is accessible.
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 template <typename ContextT>
 class pp_iterator
 :   public boost::spirit::classic::multi_pass<
         boost::wave::impl::pp_iterator_functor<ContextT>,
         boost::wave::util::functor_input
     >
 {
 public:
     typedef boost::wave::impl::pp_iterator_functor<ContextT> input_policy_type;
 
 private:
     typedef
         boost::spirit::classic::multi_pass<input_policy_type, boost::wave::util::functor_input>
         base_type;
     typedef pp_iterator<ContextT> self_type;
     typedef boost::wave::util::functor_input functor_input_type;
 
 public:
     pp_iterator()
     {}
 
     template <typename IteratorT>
     pp_iterator(ContextT &ctx, IteratorT const &first, IteratorT const &last,
         typename ContextT::position_type const &pos)
     :   base_type(input_policy_type(ctx, first, last, pos))
     {}
 
     bool force_include(char const *path_, bool is_last)
     {
         bool result = this->get_functor().on_include_helper(path_, path_,
             false, false);
         if (is_last) {
             this->functor_input_type::
                 template inner<input_policy_type>::advance_input();
         }
         return result;
     }
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 }   // namespace wave
 }   // namespace boost
 
 // the suffix header occurs after all of the code
 #ifdef BOOST_HAS_ABI_HEADERS
 #include BOOST_ABI_SUFFIX
 #endif
 
 #endif // !defined(BOOST_CPP_ITERATOR_HPP_175CA88F_7273_43FA_9039_BCF7459E1F29_INCLUDED)