Boost.Wave: A Standard compliant C++ preprocessor library
http://www.boost.org/

Copyright (c) 2001-2013 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)
-------------------------------------------------------------------------------

TODO (known issues):
- Fix expansion of macros, which replacement-list terminates in a partial
  macro expansion.
- Try to remove the second parameter from the pp_iterator<>::force_include
  function.
- Fix the trigraph backslash problem in the re2c (C/C++ and IDL) scanners, if
  there is the end of the (internal) buffer just in between a '??/' and a '\n'.

-------------------------------------------------------------------------------

CHANGELOG

Boost V1.79:
  - Removed support for C++03 (as a compiler) - previously deprecated in 1.74
  - Fixed #135: Comma operators in array subscripts are deprecated in C++20
  - Fixed #137: Simple unknown directive => found_unknown_directive is not called, stripped of pound.
  - Fixed #138: Empty ifdef block does not emit line directive for missing whitespace
  - Fixed #143: Parsing __has_include() fails with trailing tokens
  - Fixed #145: Sanitizer complains about reset_version()
  - Fixed #147: bitwise operations between different enumeration types are deprecated

Boost V1.75:
  - Introduced C++20 tokens, including the spaceship operator
  - Fixed #94: Tricky line number tracking logic for __LINE__ and __FILE__

Boost V1.74:
  - Fixed TRAC #10733: Hooks not called for expanding specific predefined macros
  - Fixed #58: C++11 long long literals must use consistent case
  - Repaired two samples and added a new one for macro naming enforcement
  - Implemented C++20 changes for variadic macros, including __VA_OPT__()
  - Added C++17 feature __has_include()
  - Deprecate C++98 and C++03. Support will end with 1.77.

Boost V1.73:
  - Fixed TRAC #7822: waveidl sample does not use the IDL lexer
  - Fixed TRAC #9874: Turning off 'include_next' support breaks include
  - Fixed a typedef shadowing a class (MSVC warning 4458) - Conrad Poelman
  - Updated waveidl to match recent changes in the RE2C lexer
  - Samples now build cleanly
  - Ensured samples and wave driver are covered by continuous integration

Boost V1.55:
 - Fixed #8848: Wave driver improperly processes 0xFFFFui64 token
 - Fixed #9098: Wave driver option --c++0x invalid

Boost V1.54:
 - Fixed #8478: Make Boost.wave compatible with Clang's -Wimplicit-fallthrough
   diagnostic.

Boost V1.53:
 - Fixed a problem with context<>::add_macro_definition which sometimes
   appended a superfluous T_EOF to the macro replacement list.

Boost V1.52.0:
 - Added util::create_directories() wrapper to account for new behavior of
   boost::filesystem::create_directories().
 - Fixed an obscure problem when preprocessing directives wouldn't be recognized
   if the previous line contained nothing but an empty macro invocation
   (see new test case t_9_023.cpp)
 - Added a new command line option --license=<file> to the Wave driver tool
   which allows to pre-pend the content of a (license) file to every newly
   created file. This option simplifies the implementation of partial
   preprocessing as done on Phoenix, Fusion, etc.
 - Changed the effect of the -N command line option to simply not expand
   the macro by pretending it was not defined. Earlier the whole invocation
   sequence was skipped, now we skip only the macro itself, which still expands
   the arguments for the macro invocation.
  - Fixed a couple of compilation warnings

Boost V1.51.0
 - Fixed #7050: Invalid memory write bug in lexing_exception
 - Fixed #7159: Text-lines are processed as if they were preprocessing directives
 - Changed --c++0x command line option to --c++11.

Boost V1.50.0
 - V2.3.2
 - Fixed #6758: not all members are initialized by base_iteration_context
   constructor.
 - Fixed #6838: Adding include file with force_include makes Wave fail to emit
   #line directive
 - Added support for test of --forceinclude option to testwave executable,
   added test case verifying #6838 is fixed.
 - Fixed #6870: build wave driver failed

Boost V1.48.0
 - V2.3.1
 - Added the flag support_option_emit_contnewlines allowing to control whether
   backslash newline sequences are emitted by the Wave library. The default is
   as before: these tokens will be silently ignored (after the token positions
   have been properly updated). Note: this option is supported by the SLex lexer
   module only.
 - Fixed #5887: flex_string.hpp needs to include <ios>

Boost V1.47.0
- V2.3.0
- After preprocessing the body of any #pragma wave option() the wave tool now
  concatenates all adjacent string literals into a single string literal.
- Fixed whitespace handling, added a corresponding set of test cases
  (t_9_020.cpp)
- Added a new preprocessing hook: locate_include_file allowing to customize the
  way include files are located.
- Added new command line option --noexpand/-N to the Wave driver allowing to
  suppress macro expansion for a given macro name (works for both, object like
  and function like macros). This option has to be used very carefully as it
  not only leaves the whole macro invocation untouched in the generated output
  but also removes this macro from consideration for Wave itself. This can
  cause unexpected results if the suppressed macro would influence #ifdef's
  later on.
- Fixed Wave driver to retain all macros defined on the command line in
  interactive mode.
- Fixed problem #5554: wave slex parser eof without eol skips the last line.
- Added the compile time configuartion option BOOST_WAVE_WCHAR_T_SIGNEDNESS,
  which can be set to BOOST_WAVE_WCHAR_T_AUTOSELECT, BOOST_WAVE_WCHAR_T_FORCE_SIGNED,
  or BOOST_WAVE_WCHAR_T_FORCE_UNSIGNED), it defaults to autoßselect.
- Fixed a problem in teh wave driver tool related to #pragma option(output).
  If wave was invoked in rapid succession this erroneously appended to an
  existing file instead of overwriting that file.
- Fixed #5569: slex CONTLINE token works only for LF line endings

Boost V1.46.0
- V2.2.0
- Added recognition of C++0x keywords to Re2C lexers.
- Added --c++0x command line option to Wave to enabling the recognition of
  C++0x keywords, converting those to C++0x tokens.
- Adapted all of the library to play well with Boost.Filesystem V3 (which is
  the default from now on).
- Added support for extended character and string literals, added test case
  (which required to add C++0x support to the test application).
- Added proper predefined macros fro --c++0x mode. __cplusplus is currently
  defined to 201101L, but this will change when the Standard is finalized.
- Fixed a problem with object like macros, which when being adjacent to a
  parenthesis, caused the parenthesis to disappear when the macro expansion
  was suppressed by the expanding_object_like_macro() hook function.
- Fixed a bug in pragma option(preserve), missing to set to preserve=1 if
  after the previous value was preserve=2.
- Changed the --preserve option of the wave tool to interprete the integer
  argument in a slightly different way:
      0: no whitespace is preserved,
      1: only begin of line whitespace is preserved,
      2: only begin of line whitespace and comments are preserved,
      3: all whitespace is preserved
  The #pragma wave option(preserve) now supports these arguments:
  [0|1|2|3|push|pop].

Boost V1.45.0
- V2.1.0
- Token pasting is well formed only as long as the formed token(s) are
  pp_tokens as defined by the C++0x Standard. Until now, Wave allowed for
  non-pp_tokens to be formed in --variadics mode.
- Fixed a problem, which prevented reporting /##/ in a macro definition as
  invalid token pasting.
- Fixed problem preventing the skipped_token hook to be called for 'inactive'
  conditional preprocessing directive tokens. Improved overall consistency in
  reporting skipped tokens to the hooks function when processing conditional
  preprocessing directives. Added a new test case verifying the skipped_token
  hook gets called reproducibly (t_2_020.cpp).
- Fixed a problem with the pp hooks 'expanding_object_like_macro' and
  'expanding_function_like_macro', which when returning true were stopping all
  preprocessing instead of just inhibiting the expansion of the macro.
- Fixed a duplicated call to the pp hook skipped_token for preprocessing
  directives inside inactive conditional branches.
- Changing exception handling to fix clang++ regression errors.
- Replaced assert() with BOOST_ASSERT to pacify the Boost inspect tool.

Boost V1.44.0
- V2.0.6
- Added information about the file type to iteration context. This can be
  either main_file, system_header, or user_header depending whether the handled
  file is the main file to preprocess, a include file opened from `#include <>`,
  or a include file opened from `#include ""`.
- Added support for new Boost visibility macros. Properly exported all
  exceptions, etc.

Boost V1.43.0
- V2.0.5
- Fixed the wave driver application to strip leading and trailing whitespace
  from macro names specified on the command line using -U.
- Fixed line number counting for lines containing nothing but whitespace
  followed by a C++ comment if the next line is a pp directive.
- Fixed emitting of a #line directive after returned from an include file.
- A couple of fixes allowing to properly report the current line number in
  #line directives for different whitespace preserve modes (see --preserve/-p).
- Added new preprocessing hook: emit_line_directive, allowing to customize the
  format of the generated #line directive.
- Changed --line/-l command line option of the wave driver application to
  accept 0, 1, and 2 as options. The option values 0 and 1 behave as before
  (disable/enable the generation of #line directives), while the option value 2
  will generate the #line directive using the relative filename (instead of the
  absolute filename emitted from option 1). The default option is value 1.
- Added new example: emit_custom_line_directives, demonstrating the use of the
  new preprocessing hook.
- Added new preprocessing hook: found_unknown_directive, which is being invoked
  whenever an unknown preprocessor directive (i.e. '#' followed by some
  identifier) is detected. It allows to interpret the directive and to provide
  some replacement text.
- Added new example: custom_directives demonstrating the usage of the new
  preprocessing hook.
- Fixed #4113: cpp_lexer does not handle qualified backslashes correctly.
- Fixed #3106: wave on VS2010 beta compiler generates error.

Boost V1.42.0
- V2.0.4
- Fixed Wave for latest changes in multi_pass iterator.

Boost V1.41.0
- V2.0.3
- Switched to Re2C V0.13.5
- Fixed --list_includes/-l command line option of the wave driver tool to
  correctly indent the generated list of included files.
- Finally fixed all remaining examples. Everything seems to work fine now.
- Specifying a custom token type now works as expected. The new lexer interface
  introduced in V2.0 broke this part.
- Removed old code related to pre Boost V1.31 (related to V1 of iterator
  library).
- Added a new commandline option --macrocounts/-c to the Wave driver application
  which lists all macro invocation counts to an optionally specified file
  (default is cout).
- Fixed compilation problems caused by recent changes to the multi_pass iterator
  from Spirit V2.1.
- Added the new preprocessing hooks detected_pragma_once() and
  detected_include_guard() which are getting called whenever either a #pragma
  once has been detected or if the include guard heuristics detected an
  include guard for a particular include file.
- Added a new command line option to the wave driver tool: --listguards/-g
  allowing to trace all include files which are either contain a #pragma once
  or contain include guards.
- Started to elminate g++ struct aliasing warnings (more to fix, mostly in
  flex_string).

Boost V1.40.0
- V2.0.2
- Fixed a long standing race condition inhibiting to use Wave in multi threaded
  environments.
- Incorporated the changes from latest version of the flex_string class (#2946).
- Fixed another race condition triggering problems using Wave in multi-threaded
  environments.

Boost V1.39.0
- V2.0.1
- Fixed Wave to compile with BOOST_FILESYSTEM_NO_DEPRECATED defined (i.e. the
  library doesn't use the deprecated filesystem interface anymore).

Boost V1.37.0
- Updated examples to reflect the recent changes in the used multi_pass
  iterator.
- Fixed documentation links still pointing to the old Boost CVS (thanks to
  Jürgen Hunold for providing the patch).

Boost V1.36.0
- Wave Version 2.0 is a new major release introducing some breaking API changes,
  preventing it to be used with Boost versions earlier than V1.36.0. The API
  and hook interface have been streamlined for more consistency. See the
  documentation for more details.

- Added an additional template parameter to the context object, allowing to
  specify any possibly derived type. This change propagates to the preprocessing
  hooks, which now get passed the most derived context type as its first
  argument allowing to access protected members in the original context type.
  This fixes ticket #1752.
- Fixed a problem during parsing of #pragma wave directive, where the value
  sequence contained a closing parenthesis. This caused a premature end of the
  pragma value parsing.
- Fixed handling of support_option_single_line, which was ignored under certain
  circumstances.
- Fixed ticket #1766: Wrong evaluation of conditional preprocessor directives
  with predefined macros __FILE__, __LINE__ and __INCLUDE_LEVEL__. This bug
  triggered an error in constructs like #ifndef __FILE__. Thanks to Daniel
  Wadehn for reporting and supplying a patch. Added corresponding regression
  test: t_2_018.cpp.
- Fixed a bug which reported a valid macro redefinition as invalid if the macro
  replacement text referred to a second or higher parameter of this macro.
- Fixed a problem in the wave tool to allow two errors to occur while
  preprocessing two consecutive tokens.
- Adjusted Spirit header includes to point to conform to the new directory
  structure, removed support for Spirit versions earlier than V1.7.
- Started to migrate to new multi_pass iterators from Spirit V2.0.

Boost V1.35.0
- Wave Version 1.3
- Changed the return value of the 'evaluated_conditional_expression()' pp hook
  to 'bool' allowing to force Wave to re-evaluate the current conditional
  expression. This was suggested by Felipe Magno de Almeida.
- Added a wave::context object as first parameter to all pp hook functions.
  This is an interface compatibility breaking change. The new pp-hooks can be
  disabled by defining the BOOST_WAVE_USE_DEPRECIATED_PREPROCESSING_HOOKS
  compile time constant to something not equal to zero. By default this
  constant will be defined to zero for Boost V1.35.0 and newer, switching to
  the new interface by default.
- Added optional support for the import keyword (needed for the C++ module
  proposal). The identifier import will be recognized as a keyword, if
  the compile time constant BOOST_WAVE_SUPPORT_IMPORT_KEYWORD is defined to
  something not equal zero.
- Added new preprocessing hook functions: found_error_directive() and
  found_warning_directive() to be called when #error/#warning directives are
  encountered. This was suggested by Andreas Sæbjørnsen.
- Added a new sample to Wave: hannibal, a partial C++ parser implementation
  initially written by Danny Havenith (http://havenith-verlinden.nl/hannibal/)
  who agreed to add this here. Thanks!
- Added new preprocessing hook function: found_line_directive() to be called
  when a #line directive is encountered. This was suggested by Andreas
  Sæbjørnsen.
- Improved command line handling for the wave applet.
- Incorporated latest bug fixes for the Hannibal sample provided by Danny
  Havenith.
- Added loading of a wave.cfg file from anywhere up the filesystem hierarchy
  starting from the main input file for the wave driver applet up to the
  root of the file system.
- Added support_option_emit_pragma_directive to allow to control at runtime,
  whether unknown #pragma directives should be emitted or not. To maintain
  compatibility with earlier versions this option is by default on if the
  compile time constant BOOST_WAVE_EMIT_PRAGMA_DIRECTIVES was defined to
  be not equal to zero and it is off otherwise.
- Enabled XML serialization support.
- Added the throw_exception preprocessing hook, which gets called for every
  occurring error (whenever an exception would have been thrown). The default
  of this new hook function is to throw the corresponding exception, which
  reproduces the old behavior.
- Implemented a new preprocessing hook: generated_token(), which get's called
  whenever a token is about to be returned form the library. This function may
  be used to alter the token before it gets returned to the calling
  application.
- Added a new sample 'real_positions' demonstrating the new generated_token()
  preprocessing hook and showing how to use Wave with a new token type without
  using a new lexer type.
- Factored out the pure lex_input_interface to simplify writing different lexer
  types for Wave.
- Added the token_statistics sample showing how to use Xpressive to build a
  lexer for Wave.
- Changed the list_includes sample to use a lexer which is based on the lexertl
  library written by Ben Hanson (http://www.benhanson.net/lexertl.html).
- Added a new support_option: insert_whitespace, allowing to switch off
  whitespace insertion which is normally (by default) in place to disambiugate
  C++ tokens, which would otherwise form different tokens in the output.
- Added a new commandline option to the Wave applet: --disambiguate, allowing
  to control whitespace insertion. The default value for this option is
  --disambiguate=1, resembling the previous behaviour. Specifying the option
  --disambiguate=0 allows to suppress whitespace insertion alltogether.
- Added pragma option values push and pop to the line, preserve and output
  options allowing to store and restore the current option. The syntax is:
    #pragma wave options(<option>: push) and
    #pragma wave options(<option>: pop)
  where <option> may be line, preserve or output. Thanks to Eric Niebler for
  suggesting this feature.
- Added the possibility to use static pre-compiled DFA tables for the lexertl
  based lexer.
- Incorporated the changes from Andrei's latest version of the flex_string
  class.
- Added the is_macro_defined(name) function to the context object as described
  in the documentation. This function is usable with any string type compatible
  with std::string.
- Changed behavior of the --force_include functionality, which now looks for
  the file to be (force-)included in the current directory first.
- Switched to Re2C V0.11.2
- Added const specifiers to some of the context member functions.
- Fixed a problem in the SLex C++ lexer (cpp_tokens example).
- Fixed a runtime problem in the Re2C generated lexers when fed with
  empty input files (thanks to Leo Davis for reporting and providing a patch).
- Added the is_eoi() function to token classes, returning true if the token
  has been initialized to be the end of input token (T_EOI) (thanks to Ovanes
  Markarian for suggesting this).
- Added missing #includes <cstring>, <cstdlib>, and <new> to flex_string.hpp.
- Added missing #include <climits> to cpp_chlit_grammar.hpp.
- Changed found_include_directive hook function to return a bool indicating,
  whether the file should be included (true) or skipped (false). Thanks to
  Felipe Magno de Almeida for suggesting this feature.
- Added code to the wave driver applet ignoring a #import directive (the whole
  directive is passed through to the output) whenever the pp constant
  BOOST_WAVE_SUPPORT_MS_EXTENSIONS is defined to something not equal to zero.
- Fixed the wave driver applet to correctly continue after a error or warning.
- Added a macro introspection facility allowing to iterate on all defined macro
  names.
- Added a new commandline option --macronames/-m to the Wave driver application
  which lists all defined macros and their definitions to an optionally
  specified file (default is cout).
- Fixed configuration to take into account thread related build settings.
- Added the BOOST_WAVE_SUPPORT_LONGLONG_INTEGER_LITERALS pp constant allowing
  to recognize large integer literals (larger in size than long/unsigned long)
  even if these do not have a 'll' suffix. This pp constant is effective only,
  if the target platform supports long long integers (BOOST_HAS_LONG_LONG is
  defined).
- The following preprocessing hooks now return a boolean value, which when
  returning 'true' cause the Wave library to skip the execution of the related
  preprocessing action:
    . found_directive: allows to skip the whole directive it is called for
    . expanding_object_like_macro: allows to skip expansion of the given object
        like macro, the macro symbol is copied to the output
    . expanding_function_like_macro: allows to skip the expansion of the given
        function like macro, the whole macro invocation (including all
        macro invocation parameters) are copied to the output without any
        further processing.
- Changed the interpretation of the return value of the found_include_directive
  preprocessing hook: a return value of 'false' now processes the file
  to be included normally and a return value of 'true' now skips the processing
  of the include file directive (the file doesn't get included).
  This change was necessary to make the return values of the preprocessing
  hooks consistent. Now return 'false' generally means: normal execution and
  return 'true' generally means: skip execution of the corresponding
  preprocessor action.
- Fixed compilation problems on gcc, fixed ambiguity with boost code (detail
  namespace was ambigious).
- Fixed predefined macro support to be thread safe.
- Added missing file to real_positions example. Thanks to Ludovic Aubert for
  spotting the problem.
- Unterminated C++/C comment diagnostics are now a warning and not an error
  anymore.
- Applied patch provided by Jens Seidel making sure every header compiles on
  its own.
- Updates to the documentation.
- Fixed a problem in flex_string::compare() (#include_next was non-functional).
- Fixed a bug in the pp hook expanding_function_like_macro(), where the seqend
  parameter was set to the first token after the closing parenthesis instead of
  pointing at it.
- Added the BOOST_WAVE_SUPPORT_THREADING allowing to explicitly control
  whether the Wave library is built with threading support enabled. If not
  defined the build settings will be picked up from the Boost build environment
  (BOOST_HAS_THREADS).
- Fixed a whitespace insertion glitch, where whitespace got inserted
  unconditionally between two operators even if one of these was a comma.
- Fixed #line directive after a macro invocation containing newlines to
  correctly reference the line number.
- Positions of macros defined on the command line now get properly reported as
  "<command line>":1:...
- Added testing of the preprocessor hooks.

Boost V1.34.0
- Wave Version 1.2.4
- Added the possibility to explicitly enable/disable the generation of #line
  directives. Added a corresponding commandline argument to the Wave driver
  tool (--line/-L) which takes either 0 or 1 as its parameter.
- Added support for #pragma wave option(command: value) directives, which
  supports the following commands:
   . #pragma wave option(line: [0|1])
        Enable/disable generation of #line directives
   . #pragma wave option(preserve: [0|1|2])
        Control whitespace preservation
   . #pragma wave option(output: ["filename" | null | default])
        Redirect output to the given file (or no output, if 'null' is specified,
        or output to the file as given on the command line, if 'default' is
        specified).
        The filename is resolved relative to the directory of the processed
        file.
  These new #pragma directives are implemented in the Wave driver tool only.
  It is possible to combine several options in one #pragma directive, i.e.
  #pragma wave option(line: 0, preserve: 2).
- Changed the signature of the may_skip_whitespace() preprocessing hook to
  additionally take the preprocessing context as its first parameter.
- Added the possibility to the Wave tool to disable initial output by
  specifying a '-' as the output file. This is useful for syntax checks only or
  in conjunction with the #pragma wave option(output: ...) to restrict the
  generated output.
- Improved error reporting in the Wave tool on bad output file stream state.
- Switched to Re2C V0.10.0
- Fixed some of the VC7.1 /W4 warnings.
- The Wave tool now creates the directory hierarchy of output files as needed.
- Applied some optimization, which causes skipping of the parsing for almost
  all preprocessor directives when the if block status is false. This gains
  upto 10-20% in speed for average applications.
- Added error diagnostic for #elif without matching #if, which was missing
  under certain circumstances.
- Avoided the evaluation of #elif expressions if one of the previous #if/#elif
  blocks of the same level was true. This gains upto another 5% of speed for
  average applications.
- The MS specific integer suffix 'i64' is now correctly supported by the Re2C
  and SLex lexer components (only when BOOST_WAVE_SUPPORT_MS_EXTENSIONS is
  defined during compilation).
- Changed the Wave tool to print the column number of an error/warning along
  with the line number. The new format is: 'filename:line:column: error text'.
- It is now possible to recover from the unbalanced #if/#endif statement
  warning in a proper way.
- The Wave library now automaticaly recognizes include guards in headers files
  and uses this information to avoid opening these header files more than once.
  This speeds up things by upto 10-20% depending on the concrete include files.
- Fixed the failing test t_6_023.cpp. Error reporting for illformed #else
  directives was broken (because of some recent changes).
- Fixed the failing test t_5_007.cpp. This was caused by the automatic include
  guard detection, which prevented the second inclusion of the specified
  include file the test was relying on.
- Added the possibility to switch off the automatic include guard detection.
- Added a new command line option to the Wave tool: --noguard/-G, which
  disables the automatic include guard detection.
- Now a header with include guards will be included correctly for a second time
  after its include guard symbol gets undefined.
- Added the generating platform to Wave's full version string.
- Made the Wave tool fully interactive when started with input from stdin and
  and output to stdout. In this mode the Wave tool preprocesses the input
  line by line and not only after receiving the full input as normally.
- Added serialization support for the wave::context object, which stores
  all information about defined macros and all #pragma once header information.
- Added the command line option --state (-s) to the Wave tool, which tries to
  load the serialized information from the file given as the argument to
  --state and save the state information at the end to the same file.
  This option is available in interactive mode only.
- Added possibility to verify the compatibility of the configuration used
  during compilation of the Wave library with the config info used for the
  application. Added a corresponding test to the Wave tool.
- Added a new predefined macro __WAVE_CONFIG__ which expands to an integer
  literal containg the configuration information the library was compiled
  with.
- Added proper versioning support to the serialization of state.
- Fixed the macro tracing information to contain the column numbers of the macro
  definitions as well (the format used is the same as for error messages).
- Fixed a memory leak in the flex_string copy on write code (thanks to Tobias
  Schwinger for reporting this bug).
- Fixed a memory corruption bug in the Re2C scanner buffer management code
  (thanks to Andreas Sæbjørnsen for spotting the bug).
- Fixed a major performance bottleneck in the lex_token class. This speeds up
  Wave for upto another 20-40% depending on the amount of macro expansions to
  perform.
- Added the BOOST_SPIRIT_USE_BOOST_ALLOCATOR_FOR_TREES and the
  BOOST_SPIRIT_USE_LIST_FOR_TREES Spirit configration constants to the
  wave_config.hpp to allow to fine tune the generated Spirit tree code. VC7.1
  gives best results when both are defined.
- Fixed a memory corruption bug triggered by a possible dangling reference.
- Fixed Wave tools startup crash when compiled with VC8.
- Added the name of the generating compiler (BOOST_COMPILER) to the full
  Wave version info.
- Fixed all Jamfile.v2 to correctly disable RTTI for VC7.1.
- Added #pragma message("...") to be optionally supported by the Wave library.
  This may be enabled by defining the BOOST_WAVE_SUPPORT_PRAGMA_MESSAGE pp
  constant to some value different from zero.
- Fixed a couple of typos in the file cpp.cpp preventing it to compile on
  gcc 4.1.0 (thanks to Richard Guenther for reporting these).
- Richard Guenther fixed another buffer overrun problem in the Re2C scanner.
- Fixed Jamfile.v2 files for all sample applications.
- Fixed a bug which lead to reporting of an illegal preprocessing directive
  inside not-evaluated conditional blocks under certain circumstances (thanks
  to Tobias Schwinger for reporting).
- Fixed '#define true ...', '#define false ...' and other constructs, i.e. the
  usage of the boolean keywords as identifiers during the preprocessing. Added
  a corresponding test case (t_9_017.cpp). Thanks to Andreas Sæbjørnsen for
  reporting.
- Corrected the Jamfile[.v2] of the waveidl sample to refer to correct file
  names (thanks to Juergen Hunold for submitting a patch).
- Fixed a bug which prevented the main iterator from returning a T_EOF token
  at the overall end of the input.
- Fixed a problem, where non-evaluated #elif directives never got passed to the
  skippen_token() pp hook (thanks to Andreas Sæbjørnsen for reporting).
- Fixed a problem in the get_tokenname() function.
- Added a missing #define BOOST_WAVE_SOURCE 1 to the wave_config_constant.cpp
  file.
- Fixed exception specifications to catch all exceptions by const&.
- Fixed predefined macros to appear to be defined at a position referring to
  a file named "<built-in>". Thanks to Andreas Sæbjørnsen for reporting.
- Fixed the Re2C lexer not to segfault on empty files anymore.
- Stripped leading and trailing whitespace for all lines in a config file (Wave
  driver tool).
- Fixed RTTI build issue for VC7.1/bjam --v2 (thanks to Rene Rivera for
  submitting a patch for the Wave Jamfile.v2).
- Fixed certain problems reported by the Boost inspection tool.
- Fixed a couple of SunPro5.8 warnings.
- Fixed a bug resulting in a crash if a macro was redefined with a shorter
  expansion list as it was defined initially. Added a corresponding test case.
- Fixed a bug causing an infinite loop when there was a missing endif in the
  main preprocessed file.
- Improved error recovery for illegal preprocessing directive errors.
- Improved error handling and error recovery for conditional expressions
  (#if/#elif expressions).
- Wave now passes 160 out of 161 tests from the MCPP V2.6.1 validation
  testsuite!
- Added new warning for invalid #line number and filename arguments
- Improved error diagnostics for invalid #line directives containing arbitrary
  tokens after at the end of the line.
- Improved error handling wrt the misuse of the __VA_ARG__ token in macro
  definitions.
- The warning, that a file is not terminated by a newline is now issued for all
  files, not only for the main file (as previous).
- Added a couple of new test cases to verify various diagnostics.
- Fixed wave applet not to report missing #endif's when in interactive mode.
- Cleaned up the Re2C lexer code.
- Fixed a bug, where a empty line followed by an arbitrary token and followed
  by a preprocessing directive interpreted the preprcessing directive as if it
  were the first non-whitespace token on the line. This error occurred only
  if the #line directive generation was suppressed. Thanks to Joan Grant for
  reporting this problem.
- Fixed a problem in the Wave applet which prevented the correct recognition of
  Windows file paths in a configuration file, if this path was enclosed in
  quotes.
- Extended the copyright notice to include the year 2007.
- Fixed a problem in preserve=1 mode, when a C style comment triggered the
  generation of a #line directive.
- Worked around a linker issue for the True64/CXX compiler, complaining about
  multiple defined symbols when using the flex_string class.
- Added missing documentation for the context::get_macro_definition function.

Sat Feb 18 2005
- Version 1.2.3
- Added a missing throw() specification to the function
  cpp_exception::get_related_name().
- Fix Boost bug ([ boost-Bugs-1395857 ] wave redefines BSIZE).
- Added missing calls to the skipped_token() preprocessing hook which wasn't
  called for pp directives inside disabled #if blocks.
- Made the context<> type noncopyable.
- Introduced the --extended/-x command line option to the wave driver
  executable, which enables the #pragma wave system() directive. This directive
  is now disabled by default because it may cause a potential security threat.
- Changed the what() function of the macro_handling_exception class, which now
  correctly returns the name of the exception type itself.
- Added a diagnostic message to the wave driver executable, which is issued
  whenever a #pragma wave system() directive is found, but the -x (--extended)
  command line argument was not given.
- Fixed long integer suffix to be allowed to be mixed case (1Ll or 2lL).
- Fixed the BOOST_PP_CAT(1e, -1) pp-token bug. Wave now correctly recognizes
  pp-number tokens, which are converted to C++ tokens right before they are
  returned from the library.
- Moved the implementation of the token_id query functions (get_token_name(),
  get_token_value()) to a separate source file.
- Fixed a bug, which prevented to prefer pp-numbers in files preprocessed as
  a result of #include directives.
- Fixed a bug, which prevented to open #include'd files specified by an
  absolute path.
- Fixed a problem in the expression parser value type.
- Fixed a dynaload compilation problem with VC7.1 of the re2c lexer tests.

Sat Dec 24 13:33:53 CST 2005
- Version 1.2.2
- Added three new preprocessing hooks: 'found_directive', 'skipped_token' and
  'evaluated_conditional_expression' (thanks to Andreas Sæbjørnsen for the
  suggestions).
- Removed hook forwarding functions in the context_type.
- Added missing include_next case branches for get_directivename() function.
- Added new sample: advanced_hooks.
- Fixed a possible buffer overflow in the cpplexer and cpp exception classes.
- Made the cpp_grammar thread safe.
- Removed the need for the get_directivename() function. Fixed typos in the
  predefined token table.
- Removed assertions from get_token_name() and get_token_value() and replaced
  these with more meaningful code.
- Added the BOOST_WAVE_USE_STRICT_LEXER configuration constant which allows to
  decide, whether the '$' character will be recognized as a part of identifiers
  or not (the default is BOOST_WAVE_USE_STRICT_LEXER == 0, i.e. '$' will be
  recognized as part of identifiers).
- Added the possibility to testwave to extract a tagged comment based on a
  preprocessor constant (testwave V0.4.0).
- Made the predefined_macros_grammar thread safe.
- Added dll support for the generated Wave libraries.
- Added the const_iterator based exlicit instantiations for the Re2C lexer to
  the built Wave library and dll.
- Added the whitespace handling policy to the context object. This actually is
  no separate policy, it's a new preprocessing hook allowing to decide, whether
  a concrete token has to be skipped.
- Changed the --preserve option of the wave tool to take a single integer
  argument (0: no whitespace is preserved, 1: only comments are preserved,
  2: all whitespace is preserved)
- Edited the command line option descriptions of the wave driver.
- Fixed broken tags in documentation (magically inserted by DreamWeaver).
- Merged the new whitespace_handling policy with the existing preprocessing
  hooks. The name of the new preprocessing hook ist may_skip_whitespace().
- Fixed compatibility issues for CW9.4 in the Wave test aplication.
- Added get_errorcode() member to the wave exception classes allowing to
  get back the reason for the exception.
- Added boost::wave::is_recoverable(cpp_exception const&) alowing to decide,
  whether it is possible to continue after a cpp_exception has been thrown.
  This is a temporary hack to overcome the current limitation of the library
  not allowing to do generic error recovery. It allows to recover from 75% of
  the generated errors types.
- The --timer command line option for the Wave driver now prints the elapsed
  time correctly even if a preprcessing error occurred.
- Fixed an error recovery problem which skipped one token after continuing in
  case this was a pp directive.
- Added the --autooutput (-E) option to the Wave driver applet which redirects
  the generated output to a file named after the input file changing the file
  extension to '.i'.
- Changed all throw's to boost::throw_exception.
- Added the possibility to configure the command keyword for the wave specific
  #pragma directives. It is now possible to define a string literal via
  BOOST_WAVE_PRAGMA_COMMAND, which will be recognized and all corresponding
  #pragmas are dispatched to the interpret_pragma() preprocessing hook.
  The default value for BOOST_WAVE_PRAGMA_COMMAND is "wave", just to ensure
  complete backward compatibility.
- Added missing #pragma warning(pop) directives.
- Fixed a bug wrt error propagation in the expression parser.
- Fixed an assertion fired when cpp_token is used to process the quick_start
  sample.
- Fixed a (Windows specific) bug which triggered a boost::file_system exception
  under certain conditions.
- Switched to Re2C V0.9.11
- Fixed a problem with the new '-E' (--autooutput) option.
- Added better error reporting for duplicate macro definitions to the Wave
  tool. Added the macro_handling_exception type containing the corresponding
  macro name via the new (virtual) get_related_name() function.
- Added the get_severity() function to the exceptions thrown by the Wave
  library.
- Extended the copyright notice to include the year 2006.

Mon Dec  5 22:05:22 CST 2005
Boost V1.33.1
- Version 1.2.1
- Fixed bug reported as Sourceforge bug 1274584.
- Switched to Re2C V0.9.9.
- Fixed a bug where the 'parameters' and 'definition' parameters to the
  defined_macro callback of the preprocessing hooks were always empty (thanks
  to Stefan Seefeld for reporting).
- Fixed missing namespace specifiers in token definition macros (thanks to
  Jozsef Mihalicza for reporting).
- Enabled --preserved and --long_long modes by default for the cpp_tokens
  sample.
- Newline tokens reported a wrong line number (offset by one) when using the
  Re2C generated lexer (thanks to Jozsef Mihalicza for pointing this out).
- Changed file positions to carry 'unsigned int' line and column numbers.
- Fixed tokens of a generated #line directive to carry the correct column
  numbers.
- Tokens now contain the correct filename, line and column numbers even if
  a #line directive was encountered.
- Fixed wrong line numbering in reference comments of the tests t_5_002.cpp and
  t_5_035.cpp.
- Made sure, that preprocessor expression errors get ignored for 'passive'
  #elif branches.
- Fixed an issue reported by the gcc debug stl.
- Added the <vc-7_1-stlport><*><rtti>off directive to all of the V1 Jamfiles.

Wed Aug 17 20:21:00 CST 2005
Boost V1.33.0
Version 1.2
- Fixed name clash wrt T_DIVIDE on FreeBSD.
- Fixed documentation of the different language_support flags.
- The support for long long suffixes is no longer bound to the variadics mode,
  it has to be enabled by the new long_long mode (default in C99).
- Fixed compilation if BOOST_WAVE_DUMP_PARSE_TREE is defined.
- Fixed lexer error message wrt long_long mode.
- Stefan Seefeld fixed a bug in the lexer, where include_next was assumed for
  included files containg a "include_" in their name.
- Fixed some trigraph token id's in the lexers.
- Added column information to the re2c generated lexer.
- Added tests for the different lexers.
- Fixed the found_include_directive preprocessing hook to carry the information
  about #include_next directives as well.
- Separated the different lexer tests.
- Fixed a bug in the whitespace eater.
- Fixed a bug where Wave emitted the found C++ comments in --preserve mode even
  if these were found inside of disabled #if/#endif blocks.
- Removed the function local static grammars to avoid possible raise conditions
  and to make CW8.3 happy.
- Unified lexer interface, adjusted namespaces.
- Added lexer testcases to the regression tests.
- Fixed test cases to scale to 64 bit platforms.
- Disabled the MS specific extensions in the lexer tests in a platform related
  way.
- Added special handling of the eof tokens inside the lexer iterator classes
  for Comeau.
- Applied a workaround proposed by David Abrahams to make the slex lexer work
  on the CodeWarrior platforms.

Sun May  8 17:22:59 WEDT 2005
Version 1.1.17
- Added ill_formed_character_literal and ill_formed_integer_literal errors.
- Improved error handling and diagnostics for integer overflow in #if/#elif
  expressions.
- Fixed a bug in the testwave application which prevented the correct
  recognition of expected errors under certain circumstances.
- Fixed a portability problem (for gcc 3.3.x) in the testwave application.
- Enforced that #if/#endif are balanced file wise.
- Changed the command line arguments for the Wave testrun to use absolute
  directories.
- Changed the test application to return a value != zero if one of the given
  config files were not found.
- Fixed a command line parsing problem caused by a change in the parameter
  handling inside in the program_options library.
- Switched to the most recent version of re2c (V0.9.7.dev).
- Fixed a como compilation error and several como --a warnings.
- The T_EOF token doesn't carry the value of the previous token anymore.
- Added operator==() to the token classes to fix the ambiguity error reported
  by the True64 compiler.
- Improved the error message, when empty arguments are used in pure C++ mode.
- Added character literal out of range testing and an additional corresponding
  error message.
- Fixed parsing of long character literals (such as '\x1234').
- Fixed almost all problems diagnosed by the Boost inspection report.
- Several fixes to make the True64 compiler happy.
- Added the long long suffix handling to the C99 mode (LL/ll).
- Fixed a bug in the slex regex specifications.

Thu Apr  7 10:07:45 WEDT 2005
Version 1.1.16
- Fixed a bug in the white space eating component, which prevented a C++
  comment to be suppressed if it followed after another whitespace.
- Fixed the inconsistencies between the documentation and the behaviour wrt the
  different include search paths. See the Wave driver docs for details of how
  the '-I', '-I-', and '-S' options work.
- Allowed to specify more than one config file ('@' syntax) on the command line
  of the wave driver executable.
- Changed copyrights in all files to reflect the acceptance of Wave into Boost.
- Unknown preprocessing directives were not recognised as such anymore.
- If comments shouldn't be preserved all C++ comments are replaced by newline
  tokens (instead of beeing igored completely).
- Fixed a bug in the white space eater component.
- Fixed a bug which reported wrong line numbers for error encountered during
  retokenisation (concatination).
- Fixed a bug in the unescaping code.
- Fixed a compilation error of the testwave executable (added a missing
  namespace specifier).
- Added a missing header to make cpp.re.cpp compile on CW.
- The predefined macro __BASE_FILE__ now returns a properly escaped file name
  string.
- Fixed the function boost::wave::util::impl::unescape_lit().
- Added the Wave unit test framework. For now it contains about 60 unit tests
  executed by a special test driver (testwave).
- Added the '$F' replacement string to the testwave application. This allows
  to handle file paths sensitive comparison of the expected and real results.
- Fixed a minor problem in the whitespace eating component.
- Added optional trigraph conversion.
- Changed all size_t, time_t etc. to std::size_t, std::time_t etc (for CW).
- If the comments should not be preserved every C comment containing at minimum
  one newline is now converted to a newline token.
- Added the lexed_tokens sample.
- Fixed warnings and errors reported by the CodeWarrior compiler.
- Added the '$V' replacement string to the testwave application. It expands to
  the current BOOST_LIB_VERSION.
- Diagnosed the attempt to redefine the alternative operators as and, or etc.
- Improved error handling.
- Disabled the flex_string class for VC7, enabled to fallback to std::string
  for this compiler.
- Renamed files to comply with the Boost rules.
- Added the first part of the MCPP validation suite to the Wave unit tests.
- Added even more missing "using namespace std;" statements for functions from
  the C runtime library. The Wave test suite now contains more than 100 unit
  tests.
- Added the $P/$P(basename) replacement string to the testwave application
  which expands to the full path of the current file ($P) or to the current
  directory/basename ($P(basename)).
- Fixed a bunch of portability problmes revealed by the regression tests on
  different platforms. Thanks to Stefan Slapeda for his support to make it work
  on the cw-9_4 toolset (win32).

Tue Mar 22 14:52:45 WEST 2005
Version 1.1.15
- Fixed a bug where the complete set of C99 predefined macros were pre-defined
  when in C++ mode and variadics were enabled.
- When in variadics or C99 mode the __BASE_FILE__ predefined macro expanded to
  <Unknown>.
- Added the --listincludes option to the Wave driver executable which allows to
  log the file names of the include files opened.
- Fixed a gcc warning in token_cache.hpp (unused variable end).
- Changed the logic behind #include_next. It now starts searching with the
  next directory after the directory the current file (the file containing the
  #include_next directive) is located in.
- Changed the signature of the undefined_macro preprocessing hook to take the
  token itself and not the macro name only. This is important to pass the full
  context information about the position of the #undef directive to the
  user provided hook (thanks to Stefan Seefeld for pointing that out).
- Fixed several broken links in the Context Policy topic.
- Fixed a bug in the handling of the #include_next directive inside of
  non-evaluated #if blocks.
- Fixed a bug in the #include_next handling code (thanks to Stefan Seefeld).
- Changed the signature of the opened_include_file() preprocessing hook which
  now receives not only the absolute file name of the openend include file but
  additionally gets passed the (possibly) relative path of the openend include
  file. This concrete format of the relative path depends on the format of the
  include search directory given to the library.
- Added a new preprocessing hook 'found_include_directive()' which gets called
  for every #include directive (even for those where the file to include
  doesn't exist) and which gets passed the (expanded) token sequence found
  after the #include directive token.
- The file names passed to the preprocessing hooks are now normalised.
- Changed the opened_include_file() preprocessing hook to receive the correct
  relative path even if the included file was found in the current directory.
- Fixed a bug which reported 'defined(or)' as invalid (similarly all the other
  alternative bit operation token types).
- Fixed a bug which prevented to define variadic macros from the command line.
- Added a 'preserve comments' mode to preserve the comments in the input stream
  not inserted into macro definitions.
- Added a new --preserve (-p) command line switch to the wave driver
  application to allow comments to be preserved in the generated output stream.

Mon Feb 21 09:30:04 WEST 2005
Version 1.1.14 (Fixes in response to the Boost review)

Wave was accepted into Boost!

With special thanks to Tom Brinkman, who volunteered to be the review manager.

With thanks to David Abrahams, Beman Dewes, Reece Dunn, Larry Evans,
Doug Gregor, Joel de Guzman, Baptiste Lepilleur, Andy Little, Paul Mensonides,
Dan Nuffer, Andreas Pokorny, Vladimir Prus, Gennadiy Rozental, Michiel Salters,
Jonathan Turkanis, Chris Uzdavinis, Pavel Vozenilek, Michael Walter for bug
reports, fixes and hints.

- Added support for the MS extensions #region and #endregion, which simply get
  ignored by Wave. The support for these is enabled only, when the pp constant
  BOOST_WAVE_SUPPORT_MS_EXTENSIONS is defined. Otherwise these get flagged as
  an illegal preprocessor directive (as before).
- Fixed a problem, where the replacement text for a #pragma directive got lost
  if this directive was on the last line of a processed (include-)file.
- Changed the default value for BOOST_WAVE_SUPPORT_MS_EXTENSIONS for non-
  Windows systems to zero.
- Updated outdated external links in the documentation.
- Fixed certain grammatical and stylistic quirks in the documentation.
- Fixed a problem in libs/wave/build/Jamfile.v2 (as reported by Larry Evans).
  Fixed the Jamfile.v2 in the samples directories accordingly.
- Added the '<toolset>vc-7_1:<rtti>off' to all Jamfile.v2 files to adjust for
  the internal buffer overflow bug in the VC7.1 compiler (reported by Joel de
  Guzman).
- Changed the '<toolset>vc-7_1:<rtti>off' to '<toolset>vc-7.1:<rtti>off' as
  required by the Boost.Build.v2 library (suggested by Vladimir Prus).
- Finally fixed the Jamfile.v2 file (after a suggestion from Reece Dunn)
- Fixed the column number reported for tokens for Slex lexer based
  configurations (reported by Baptiste Lepilleur).
- Added the __BASE_FILE__ predefined macro, which contains a string literal
  of the main file name to preprocess (the one the context<> template was
  created with). (suggested by Pavel Vozenilek)
- Used the boost::reverse_iterator instead of the std::reverse_iterator
  for the flex_string class to allow compilation of Wave with VC7.0
  (as suggested by Reece Dunn).
- Fixed a problem in the include_path template, which throwed a
  boost::filesystem exception whenever a character was used in a file name
  to include, which is marked as illegal by the default name checker of the
  boost::filesystem::path.

Version 1.1.13 (Boost review candidate 2, bug fixed version)
- Fixed a problem, where the context<> template referenced temporary iterator
  objects from the underlying stream (thanks to Michiel Salters for reporting
  this).
- Fixed a bug in the re2c lexer, which allowed to dereference the end iterator
  of the underlying input stream (thanks to Doug Gregor for pointing this out).
- Fixed several assertions fired by the iterator checking code of the VC8 stl.

Version 1.1.12 (Boost review candidate)
- A rough performance analysis showed, that 30% of the time is spent parsing
  the input for pp directives (cpp_grammar), 35% of the time is spent inside
  the flex_string code, mainly in the copy constructor and assignment
  operator, 15% of the time is spent inside the list and vector member
  functions, 10% is spent for memory allocation but only 1% of the time is
  spent in the re2c lexer.
- Identified a performance problem, where the token_cache was instantiated
  for every created lexer object, but needed to be initialised only once.
- Added #include <wave_version.hpp> to wave_config.hpp
- Fixed problems reported by the gcc 3.4.1 compiler.
- Adjusted Jamfiles for the new toolset names introduced in Boost V1.32.

Version 1.1.11
- Updated copyrights.
- Fixed some bugs introduced by the latest refactoring.
- Tried to fix the expansion of macros, which replacement-list terminates in a
  partial macro expansion. No success so far.

Version 1.1.10
- Refactored some of the macro map (macro namespace) code (added comments,
  splitted into separate files),
- Fixed some typename errors in cpp_macromap.hpp (thanks to Vladimir Prus).
- Fixed the BoostBuild V2 Jamfiles (thanks to Vladimir Prus).

Version 1.1.9
- Moved all of the #pragma wave option(value) operators out of the wavelib into
  the wave driver program. Removed enable_trace() and trace_flags() policy
  functions. Renamed trace_policy into context_policy.
- Added the defined_macro() and undefined_macro() preprocessing hooks to allow
  easily to build macro cross referencers and such.

Version 1.1.8
- Replaced the usage of the string::erase() and string::insert() functions,
  which were the only non-const string member functions used.
- Token pasting is now well defined in variadics mode (was in C++0x mode only).
- Changed the timing code in the wave driver to include the parsing of
  files included by the --forceinclude command line switch.
- Performance measurements (very informal) [sec], the files are some of the
  preprocessor specific test cases from Paul Mensonides chaos_pp library.

                        std::string   flex_string   const_string   const_string
                                                      12 Byte        28 Byte
    arithmetic.cpp        2.543          1.742         0.951           1.001
    array.cpp             2.453          1.762         0.951           1.011
    comparison.cpp        0.560          0.340         0.270           0.280
    control.cpp           0.590          0.340         0.290           0.300
    debug.cpp             0.370          0.310         0.190           0.190
    detection.cpp         0.050          0.060         0.030           0.030
    extended.cpp          0.370          0.260         0.190           0.190
    facilities.cpp        0.610          0.340         0.290           0.300
    iteration.cpp         1.081          0.550         0.410           0.450
    list.cpp              1.742          1.141         0.811           0.851
    logical.cpp           0.070          0.200         0.040           0.040
    punctuation.cpp       0.030          0.080         0.020           0.020
    repetition.cpp        1.392          0.851         0.650           0.690
    selection.cpp         0.440          0.270         0.210           0.220
    slot.cpp              0.680          0.350         0.240           0.270
    tuple.cpp             0.420          0.240         0.190           0.210


Wed Aug 25 13:23:27 WEDT 2004
Version 1.1.7
- Branched for Boost Release.
- Removed several features from the code base:
  . removed C++0x support
  . removed TST support
- Fixed the program_option validator syntax, which has changed since the last
  update.
- Removed misleading configuration options from the cpp_config.hpp file,
  because the application will have to use the same config options as were used
  during the compilation of the library.
- Changed the naming convention of typedef'd types in the library. Removed the
  _t suffix, wherever possible.
- Updated the documentation to reflect the removal of the C++0x features.

- Changed the licensing scheme to:
// Copyright 2004 Joe Coder. 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)

Mon May 24 10:02:47 WEDT 2004
Version 1.1.6
- Fixed a incompatibility with the new program_options version.

Version 1.1.5
Version 1.0.6
- Fixed a bug, which reported an #include statement as ill formed, if it was
  followed by an empty C comment only. This was an error in the cpp.re regular
  expression for C comments. Additionally, since this change simplified the
  Re2C generated lexer a lot it was possible to remove the compiler workaround
  for the VC7.1 compiler which prevented the optimization of this lexer.

Mon Mar 29 09:36:59 WEDT 2004
- Corrected the signature of the main() functions (was main(int, char const*[])).

Sun Mar 28 12:55:59 WEDT 2004
Version 1.1.4
- Fixed a problem, where the first returned token was lost, whenever a
  --forceinclude file was given.
- Adjusted the Wave driver and the other samples to use the new program_options
  library syntax (V1.1.x only).

Mon Mar  1 19:14:21 WEST 2004
Version 1.1.2
Version 1.0.4
- Fixed a problem, which does not report an error, if in a #define statement in
  between a macro name and its replacement list were no whitespace given.
- Fixed a bug, which generated an unexpected exception of the $ character in the
  input.
- Macro definitions, which differ by whitespace only (one definition contains
  whitespace at a certain position, the other definition does not) are correctly
  reported as a warning now.
- Fixed a problem, where different formal argument names during macro
  redefinition were not flagged as a warning.
- A wide character string used in a #line directive wasn't flagged as an error.

Sun Feb 29 19:10:14 WEST 2004
Used the test suite distributed with the mcpp V2.4 preprocessor to fix a bunch
of mostly minor issues:
- Fixed trigraph backslash followed by a newline handling (??/ \n) in the
  re2c (C/C++ and IDL) scanners.
- Fixed a digraph/trigraph token type handling problem during macro expansion.
- Fixed a digraph/trigraph token type problem during handling of the null
  preprocessor directive.
- Fixed several signed/unsigned conversion bugs in the expression evaluator.
- Fixed the || and && operators in the expression evaluator to stop evaluation,
  as only the outcome of the overall expression is determined.
- Fixed the expression evaluation engine to detect divide by zero errors.
- Fixed a bug with operator || and && arithmetic (the deduced type was wrong).
- Fixed a bug with the unary operators ! and - which IN conjunction with an
  arithmetic operation yielded A wrong result type.
- Fixed a bug, which reported a macro definition as an invalid redefinition, if
  it was different from the original definition only by different whitespaces.
- Fixed a bug, which reported the redefinition of one of the alternative tokens
  as 'and', 'bit_and' etc. as invalid.
- Fixed a bug in the character literal parser, which prevented the recognition
  of multibyte character literals.

- Moved the cpp_token_ids.hpp header into the main wave.hpp header, because the
  values defined therein aren't changeable by the user anyway.
- Fixed some spelling errors in the documentation (thanks to Rob Stewart).

Tue Feb  3 20:20:16 WEST 2004
- Fixed the problem, that macro definitions in a config file were flagged as
  an error, if there was any whitespace in between the -D and the macro name
  (same problem existed for -P).

Fri Jan 30 20:28:27 WEST 2004
- Fixed a missing boostification in the trace support header.
- Added a missing std:: namespace qualification to the list_includes.cpp sample
  file.
- Fixed line ending problems with the cpp.re and idl.re files.
- Added quick_start sample.

Sun Jan 25 20:26:45 WEST 2004
This version was submitted to Boost as the review candidate (V1.1.0)
- Fixed invalid explicit instantiation syntax as reported by the Comeau
  compiler.
- Added a missing header to flex_string.hpp.

Sat Jan 24 19:47:44 WEST 2004
- Completely decoupled the used lexer from the preprocessor.
- Unfortunately had to change the template interface of the context class. It
  now instead of the token type takes the type of the lexer to use.
- Reintroduced the cpp_tokens, list_includes and waveidl samples.
  . cpp_tokens is based on the SLex lexer
  . list_includes shows the usage of the include file tracing capability
  . waveidl uses the Re2C based IDL lexer in conjunction with the default token
    type

Tue Jan 13 20:43:04 WEST 2004
- Fixed several compilation issues under linux (gcc 3.2.3, gcc 3.3, gcc 3.3.2,
  gcc 3.4, Intel V7.1)
- Fixed a compatibility problem with Spirit versions older than V1.7.

Mon Jan 12 20:39:50 WEST 2004
- Boostified the code base:
  . Moved code into namespace boost.
  . Prefixed all pp constants with "BOOST_".
  . Refactured the directory structure.
- Removed IDL mode and SLex lexer from the code base. These will be re-added as
  samples.
- Changed the Wave configuration system to be more flexible (all
     #if defined(BOOST_WAVE_...) changed to #if BOOST_WAVE_... != 0),
  which allows to configure the library without changing the code base itself

Sat Jan 10 18:17:50 WEST 2004
- Incorporated Andrei Alexandrescu's latest changes to the flex_string class,
  which resulted in an overall spedd gain of about 5-10%.

Wed Jan  7 17:46:45 WEST 2004
- Found a major performance hole! The achieved general speedup is about 50-70%.
- Added missing old MS specific extensions to the re2c lexer (_based,
  _declspec, _cdecl, _fastcall, _stdcall, _inline and _asm).
- Added support for #include_next (as implemented by gcc).
- Fixed compilation problems with gcc 3.3.1
- Avoid to look up in symbol table of a potential macro name twice.
- Added the Spirit SLex lexer sample to the Wave source tree, because it was
  removed from the Spirit distribution.
- Removed the configuration option, which allowed to reverse the names stored
  in the symbol tables.
- Implemented experimental support for using a TST (ternary search tree) as the
  container for the symbol tables.

Sun Jan  5 12:30:50     2004
- Released V1.0.0

Sun Jan  4 00:11:50     2004
- Removed tabs from the flex_string.hpp file.
- Modified the input_functor.hpp file to sqeeze out some milliseconds at
  runtime.
- The --timer option now prints the overall elapsed time even if an error
  occurred.
- Added support for #pragma once.

Fri Jan  2 22:58:54     2004
- Fixed a bug in the code, which predefines the preprocessor constants.
- Fixed a bug in intlit_grammar<> initialisation code.

Thu Jan  1 21:15:03     2004
- Fixed a bug while predefining a macro with a value through the commmand line.
- Fixed a bug, which reported a macro definition as illegal, if the redefined
  macro was a function like macro with parameters.
- Fixed a bug, if concatenation of two tokens resulted in a C++ comment start
  token.

Thu Jan  1 15:01:54     2004
- Finished license migration.

Wed Dec 31 12:23:55     2003
- Changed the copyright and licensing policiy to be Boost compatible.

Wed Dec 31 12:01:14     2003
- Fixed a problem while compiling certain headers from the Microsoft Windows
  SDK:
        #define CreateWindowA(lpClassName, lpWindowName, dwStyle, x, y,\
        nWidth, nHeight, hWndParent, hMenu, hInstance, lpParam)\
        CreateWindowExA(0L, lpClassName, lpWindowName, dwStyle, x, y,\
        nWidth, nHeight, hWndParent, hMenu, hInstance, lpParam)
  where essentially is no whitespace between the parameter list and the macro
  replacement list.
- Fixed a problem with the MS extension __declspec, which now is recognized
  correctly.

Sat Dec 27 14:48:29     2003
- Fixed remaining problems with assign/assign_a.
- Fixed some gcc warnings about signed/unsigned comparision mismatch.

Tue Nov 11 20:51:41 WEST 2003
- Changed the IDL mode to recognize identifiers only. All keywords (except
  'true' and 'false') are returned as identifiers. This allows for easy
  extension of the IDL language. The drawback is, that after preprocessing
  there needs to be just another lexing stage, which recognizes the keywords.
- Fixed a possible problem, when in between a #if/#elif directive and a
  subsequent opening parenthesis Wave finds no whitespace:
    #if(_WIN_VER >= 0x0500)
  is now recognized correctly.
  (This problem was pointed out by Porter Schermerhorn).

Sun Nov  9 21:05:23 WEST 2003
- Started to work on implementation of an IDL lexer for the TAO idl compiler.
  . Branched off the Re2C C++ lexer and related files as a starting point for
    the new IDL lexer. Added connfiguration means to allow compile time
    decision, in which mode to operatoe (C++ or IDL).
  . Implemented the Re2C based IDL lexing component.
  . Fixed all occurrences of non-IDL tokens (as T_COLON_COLON and T_ELLIPSIS)

Sat Nov  8 20:05:52 WEST 2003
- Version 1.0.0
- Munged the email addresses embedded within the source files.
- Adjusted for the new actor names in Spirit (assign_a and append_a).

Thu Aug 21 16:54:20     2003
- Removed the internally used macro 'countof()' to avoid possible nameclashes
  with user code.
- Fixed a bug, which prevented the execution of the concatination operator '##'
  while expanding object-like macros.

Tue Aug  5 10:04:00     2003
- Fixed a false assertion, if a #pragma directive started with some whitespace
  on the line.
- Added the #pragma wave timer() directive to allow rough timings during
  processing. This is done on top of a new callback hook for unrecognized
  #pragmas, which allows to easily add new pragma commands without changing
  the Wave library.
- Fixed a bug in the whitespace insertion engine, which prevented the insertion
  of a whitespace token in between two consecutive identifier tokens or a
  integer literal token followed by an identifier token.
- Fixed a bug during macro concatenation, which allowed to concatenate
  unrelated tokens from the input stream:
    #define CAT(a, b) PRIMITIVE_CAT(a, b)
    #define PRIMITIVE_CAT(a, b) a ## b
    #define X() B
    #define ABC 1
    CAT(A, X() C) // AB C
    CAT(A, X()C)  // correct: AB C, was 1
- Fixed a 64 bit portability problem.
- Added pragma wave timer(suspend) and wave timer(resume)
- Fixed a ODR problem with static initialization data for predefined macros.
- Ported the iterators to the new iterator_adaptors.
- Updated the documentation to reflect the recent changes

Sun Jun 29 12:35:00     2003
- Fixed 64 bit compatibility warnings.
- Fixed a bug, which prevented the correct recognition of a #line directive, if
  only the filename part of this directive was generated by a macro expansion.
- Fixed a bug during macro expansion of conditional expressions, which
  prevented the correct expansion of certain scoped macros.

Fri Jun 27 09:50:14     2003
- Changed the output of the overall elapsed time (option --timer) to cerr.
- Added a configuration constant WAVE_REVERSE_MACRONAMES_FOR_SYMBOLTABLE, which
  reverses the macro names while storing them into the symbol table, which
  allows to speed up name lookup especially, if the macro names are very long
  and if these share a common prefix.
- Fixed a very subtle bug, which prevented the recognition of fully qualified
  macro names during the macro expansion of conditionals expressions (for
  #if/#elif).
- Improved the error output for the illformed pp expression error.

Thu Jun 26 08:20:30     2003
- Done a complete spell check of the source code comments.

Wed Jun 25 20:33:52     2003
- Changed the conditional expression engine to work with integer numeric
  literals only. Distinguished signed and unsigned literals.
- Importing a region twice is allowed now.
- Fixed a bug, which does not removed all placeholder tokens from a expanded
  token sequence while evaluating conditional expressions (C++0x mode only).

Wed Jun 25 15:01:51     2003
- Changed the conditional expression engine to respect the type of numeric
  literals, now expressions like '#if 1 / 10 == 0' evaluate correctly (to true
  :-)
- Fixed a bug, where macro names referring to global macros (as ::A::B) were
  not correctly recognized under certain circumstances.
- Empty parameter lists for macros with ellipses only sometimes generated a
  placemarker token in the output:
    #define STR(...) #__VA_ARGS__
    STR()   // resulted in "§" instead of "" .

Wed Jun 25 08:35:06     2003
- Fixed several gcc compilation errors (missing typename's etc.)
- Fixed a compilation problem, if Wave is built on top of the SLEX scanner.
- Reformatted the --timer output from pure seconds to a more reasonable format.

Fri Jun 20 19:33:30     2003
- Changed the enable_tracing function of the tracing_policies to take a
  trace_flags variable instead of a bool, to allow to control tracing with more
  granulation.
- Added the tracing_enabled function to the tracing_policies, which returns the
  current tracing status.
- Updated the documentation of the tracing policies.

Thu Jun 19 21:45:39     2003
- Reactivated the list_includes sample with the help of the new include file
  tracing facility.

Thu Jun 19 17:55:35     2003
- Eliminated the TraceT template parameter from the macromap<> template.
- Added two hooks to the trace policy to allow to trace the opening and
  closing of include files.

Thu Jun 19 14:08:10     2003
- Added the command line option --timer, which enables the output to std::cout
  of the overall elapsed time during the preprocessing of the given file.

Fri Jun 13 09:11:29     2003
- Emitted an error message, if an ellipses was found as a formal macro
  parameter and variadics were disabled.
- Fixed a false error message, that the last line was not terminated with a
  newline, which occurred, if no output was generated by the last line of the
  source file.

Thu Jun 12 15:20:22     2003
- Fixed the recent change in argument expansion for the variadics/C99/C++0x
  mode.
- Fixed a problem, where an additional whitespace between _Pragma and the
  opening parenthesis resulted in a false error message.
- Used a pool allocator for the token sequence containers (std::list<>'s),
  which gives a speed gain of more than 60% (while profiling the Order
  library).

Wed Jun 11 22:18:54     2003
- Fixed a macro scoping/expansion problem, when a macro returned a full scope
  which is continued on the call site to form a full qualified name, the name
  wasn't recognized correctly:
    # region A
    #  define MACRO 1
    #  region B
    #   define MACRO 2
    #  endregion
    # endregion
    # define ID(x) x
    ID(A)::MACRO     // 1
    ID(A::B)::MACRO  // 2, was expanded to A::B::MACRO
- Changed the expansion of macro arguments such, that these will be expanded
  only, if the result is to be used for substitution during the expansion
  of the replacement list.

Wed Jun 11 14:40:29     2003
- Included a whitespace eating finite state machine (FSM) for minimal
  whitespace in the generated output. This was suggested by Paul Mensonides.
- Updated the acknowledgement section

Wed Jun  4 08:03:04     2003
- Fixed a bug reported by Faisal Vali, which prevented the correct evaluation
  of conditional expressions, if these referenced macro names, which expanded
  to a sequence containing non-expandable tokens.
- Fixed the above bug for #elif directives too (in the first place this was
  fixed for #if directives only)

Mon May 26 22:15:40     2003
- Added missing copyrights in several files.
- Fixed false output, if a unknown _Pragma were encountered.
- Fixed a macro expansion problem with qualified names, were constructs like
  the following were not expanded correctly:
    #define ID(x) x
    #region SCOPE
    #  define TEST 1
    #endregion
    ID(SCOPE::) TEST    // should expand to 1
- Changed #import semantics for macros from copy semantics to reference
  semantics, i.e. macros are now considered to be implicitly imported into the
  scope, where they are defined. If a macro is imported into another scope and
  the original macro is undefined, the imported macro still exists. Further,
  if the imported macro is expanded, then while rescanning the original macro
  is disabled too:
    #region A
    #  define B(x) x
    #endregion
    #import A
    B    (A::B) (*) // A::B(*)
    A::B (B)    (*) // B(*)
    B    (B)    (*) // B(*)
    A::B (A::B) (*) // A::B(*)
- Fixed a recently introduced problem, where placemarker tokens slipped through
  to the output under certain conditions (in variadics/C99/C++0x modes only).

Mon May 19 16:30:49     2003
- Fixed a bug, which prevented the recognition of the __lparen__, __rparen__ or
  __comma__ alternative tokens, if these were the first token after an emitted
  #line directive (reported by Vesa Karvonen).
- Added an optimization, that only those tokens are considered for a macro
  expansion, which may result in an expansion.

Tue May 13 18:16:26     2003
- Fixed a newly introduced problem, where a omitted argument consisting out
  of whitespace only were failed to be replaced by a placemarker token. This
  lead to problems with constructs like the following:
    #define paste(a, b, c) a ## b ## c
    paste(1, , 3)  // should expand to 13, but expanded to 1## 3
- Fixed a problem with the tracing support, which throwed an unexpected
  exception if there were too few arguments given while expanding a macro.
- Allowed to open and to import the global scope ('#region ::' and
  '#import ::').
- Fixed a bug, if more than one file was given with a --forceinclude command
  line option.

Sat May 10 21:30:29     2003
- Added __STDC_FULL_REGION__ and __STDC_CURRENT_REGION__ to the list of not
  undefinable macros.
- In normal C++ mode and C99 mode the #ifdef/#ifndef and the operator defined()
  should not support qualified names. This is fixed now.
- Updated the documentation.
- Fixed minor gcc -Wall compilation warnings.
- Added better error support for qualified names used as arguments for #ifdef,
  #ifndef and operator defined().

Sat May 10 09:51:18     2003
- Removed the feature, that the comma before the ellipsis parameter in a macro
  definition may be omitted.
- Resolved an issue with the expansion of qualified macros, when these
  qualified names were partially generated by a previous macro expansion
- Allowed to specify fully qualified names as arguments to the #region directive

Wed May  7 22:44:21     2003
- Changed the names of __SCOPE__ and __FULL_SCOPE__ predefined macros to
  __STDC_CURRENT_REGION__ and __STDC_FULL_REGION__ resp. The names are subject
  to change if the #region keyword actually will be renamed to #scope/#module
  or whatever.
- In C++0x mode it is now possible to omit the last comma before a variadics
  ellipsis in a macro definition:
    #define cat_i(a, b, c, d, e ...) a ## b ## c ## d ## e
- Fixed a bug in the stringize code, where an ellipsis to stringize resulted in
  stringizing of the first ellipsis parameter only. Preserved the original
  whitespace delimiting in between the ellipsis arguments.
- Introduced the wave::language_support enum for convenient switching of the
  supported language features throughout the library.
- Fixed a bug, which prevented the definition of the predefined macro
  __WAVE_HAS_VARIADICS__, if --variadics were given on the command line.

Tue May  6 15:49:45     2003
- Made predefined macros available at every macro scope without qualification.
- Predefined a new macro in C++0x mode: __STDC_GLOBAL__, which is defined at
  global macro scope only and equals to '1' (integer literal).
- In C++0x mode there are two new predefined macros:
    __SCOPE__:      expands to the last part of the qualified name of the
                    current macro scope
    __FULL_SCOPE__: expands to the full qualified name of the current macro
                    scope

Mon May  5 23:02:48     2003
- Fixed a problem in the new well defined token pasting code, which occurred for
  constructs like the following:
    #define is_empty(...) is_empty_ ## __VA_ARGS__ ## _other
  i.e. where two or more '##' operators were contained in the replacement text.
- Implemented __comma__, __lparen__ and __rparen__ alternative pp-tokens, which
  may be used as the ',', '(' and ')' tokens during preprocessing. These are
  only converted to there respective string representation in a special
  translation phase after preprocessing. This was proposed by Vesa Karvonen.
- Changed the macro scoping rules to: "If a qualified name does not find a
  nested name, it is not a qualified name to the preprocessor." This seems to
  be the simplest usable solution for the possible ambiguities.
- Fixed a bug in the macro expansion engine in C++0x mode, where the skipping
  of whitespace inside of a qualified name wasn't consistent.

Sun May  4 10:48:53     2003
- Fixed a bug in the expression grammar, which prevented 'not' to be recognized
  as a valid operator.
- Qualified names are now supported as parameters to #ifdef and #ifndef too.
- Remove one specialization of the macro expansion engine. It gets instantiated
  only twice now (for the main input iterator and for list<>'s  of tokens.
- Simplified the required explicit specialization of the defined_grammar
  template. It has to be explicitly instantiated by providing the token type
  only (just as for the explicit instantiations of the other grammars).

Fri May  2 22:44:27     2003
- Qualified names are now allowed as parameters to the operator defined() in
  C++0x mode.
- Separated the defined() functionality into a separate translation unit to
  work around a VC7.1 ICE.

Fri May  2 15:38:26     2003
- The C++0x mode now has a special set of predefined macros.
- The predefined macro __WAVE_HAS_VARIADICS__ is now defined in C99 and C++0x
  modes too (--variadics is implied for these modes).
- Updated the documentation to reflect the recent changes and additions.
- In C++0x mode Wave now supports macro scopes:
    - new keywords #region/#endregion/#import
    - qualified macro names
- In C++0x mode Wave now supports token pasting of unrelated tokens. These are
  concatenated, the result is re-tokenized and inserted into the output stream.
- Fixed a minor bug in the macro expansion engine, if a qualified function-like
  macro was found in an object-like context.
- Fixed an issue with well defined token pasting of unrelated tokens.

Tue Apr 29 08:47:37     2003
- Fixed a bug in the macro expansion engine, which prevented the expansion
  of a certain macro under specific conditions (if the left of two tokens to
  concatenate were a disabled one (T_NONREPLACABLE_IDENTIFIER), then the
  resulting token was disabled too).
- Added additional diagnostics to the Wave driver to disambiguate the C99 and
  C++0x modes.
- Implemented a new API function and a corresponding Wave driver command line
  option, which allows to specify one or more include files to be preprocessed
  before the regular file is preprocessed (the files are processed as normal
  input and all the resulting output is included, before processing the regular
  input file). The Wave driver command line option is --forceinclude (-F).
- Wave now compiles the Order library from Vesa Karvonen.

Mon Apr 28 07:57:10     2003
- Fixed a bug in the macro expansion engine.
- Removed a lot of (not needed) whitespace in the generated output (but still
  not optimal).

Sat Apr 26 20:30:53     2003
- Fixed a bug in the initialization code of the Slex lexer while working in
  C99 mode (reported by Reece Dunn).

Fri Apr 18 08:37:35     2003
- Fixed the handling of option_value's inside of pragma directives:
    _Pragma("wave option(option_value)")
  inside which all all whitespaces were deleted.
- Started to implement experimental macro scoping.

Thu Apr 10 10:20:07     2003
- Fixed a problem with the #pragma wave stop(), where only the first token
  inside the stop directive was output, when the preprocessor stops in result
  of this pragma.
- Implemented a new #pragma wave system(command), which spawns a new operation
  system command exactly as specified inside the system directive, intercepts
  the stdout output of this process, retokenizes this output and inserts the
  generated token sequence in place of the original #pragma or operator _Pragma.
  Please note that the generated output is _not_ subject to any macro expansion
  before its insertion as the replacement of the pragma itself. If you need to
  macro expand the replacement text, you always may force this by writing:
    #define SCAN(x) x
    SCAN(_Pragma("wave system(...)"))
  which re-scans the replacement once.
- Replaced the Wave position_iterator with the boost::spirit::position_iterator
  (without any problems!).

Mon Apr  7 10:45:30     2003
- Fixed macro_trace_policies::expand_object_like_macro not to be called with
  the formal arguments as one of its parameters.
- Updated the documentation to reflect the changes needed for the tracing
  stuff.

Mon Mar 31 19:07:05     2003
- Fixed variadics support in the trace output.
- Fixed preprocessing of operator _Pragma() before it's execution.
- Added _Pragma("wave stop(errmsg)") (#pragma wave stop(errmsg)) to allow
  diagnostics output from inside macro expansion.
- Fixed operator _Pragma for unknown pragmas (these are simply put through to
  the output).
- Implemented a maximal possible include nesting depth to avoid an out of
  memory error. The initial value for this is configurable through the compile
  time constant WAVE_MAX_INCLUDE_LEVEL_DEPTH, which defaults to 1024, if not
  given.
  Additionally this may be enlarged through a new command line option:
  -n/--nesting (Wave driver only).

Sun Mar 30 20:40:17     2003
- Implemented the predefined macro __INCLUDE_LEVEL__, which expands to a
  decimal integer constant that represents the depth of nesting in include
  files. The value of this macro is incremented on every '#include' directive
  and decremented at every end of file.
- Implemented the operator _Pragma(). It is recognized in C99 mode and whenever
  variadics are enabled.

Sun Mar 30 08:30:12     2003
- Changed the tracing format to be more readable.
- Changed the tracing #pragmas to
    enable tracing:     #pragma wave trace(enable)
    disable tracing:    #pragma wave trace(disable)
  or
    enable tracing:     #pragma wave trace(1)
    disable tracing:    #pragma wave trace(0)
- Changed the semantics of the -t (--traceto) switch. Without any -t switch
  there isn't generated any trace output at all, even, if the corresponding
  #pragma directives are found. To output the trace info to a file, the
  '-t file' syntax may be used, to output to std::cerr, the '-t-' (or '-t -')
  syntax may be used.

Fri Mar 28 17:27:25     2003
- Added a new template parameter to the wave::context<> object, which allows
  to specify a policy for controlling the macro expansion tracing. The default
  macro_trace_policy does no tracing at all. This way one can add specific
  macro expansion tracing facilities to the library.
- #pragma directives starting with a STDC identifier are no longer not macro
  expanded in C++ mode, in C++ mode these are now expanded as usual, in C99
  mode not.
- The tracing can be enabled/disabled from inside the preprocessed stream by
  inserting a special #pragma directive:
    enable tracing:     #pragma wave_option(trace: enable)
    disable tracing:    #pragma wave_option(trace: disable)
- The Wave driver now allows to specify a destination for the macro expansion
  tracing trough a new command line switch: '-t path' or '--traceto path'. If
  this option isn't given, the trace output goes to stderr.
- The Wave driver now allows to specify the name of the file, where the
  preprocessed result stream is to be saved: '-o path' or '--output path'. If
  this option is not given, the output goes to stdout.

Wed Mar 26 20:39:11     2003
- Fixed a problem with alternative tokens (as 'and', 'or' etc.) and trigraph
  tokens, which were not correctly recognized inside #if/#elif expressions.
- Alternative tokens ('and', 'or' etc.) are no longer subject to a possible
  macro redefinition.
- Fixed the special handling of 'true' and 'false' during the macro expansion
  of #if/#elif expressions.

Tue Mar 25 12:12:35     2003
- Released Wave V0.9.1

Mon Mar 24 13:34:27     2003
- Implemented placemarkers, i.e. Wave now supports empty arguments during macro
  invocations. This must be enabled by means of a new pp constant:
  WAVE_SUPPORT_VARIADICS_PLACEMARKERS which must be defined to enable the
  placemarker and variadics code and by defining the command line option
  '--variadics' (Wave driver only).
- Implemented variadics, i.e. Wave now supports macros with variable parameter
  counts. This must be enabled by means of the pp constant:
  WAVE_SUPPORT_VARIADICS_PLACEMARKERS which must be defined to enable the
  placemarker and variadics code and by defining the command line option
  '--variadics' (Wave driver only).
- Implemented a C99 mode. This mode enables variadics and placemarkers by
  default and rejects some specific C++ tokens (as the alternate keywords and
  '::', '->*', '.*'). This mode must be enabled by the means of the pp constant
  WAVE_SUPPORT_VARIADICS_PLACEMARKERS (see above). The C99 mode is enabled by
  the command line switch '--c99' (Wave driver only).
  This involved some changes in the C99/C++ lexers.

Fri Mar 21 16:02:10     2003
- Fixed a bug in the macro expansion engine, which prevented the expansion of
  macros, which name was concatenated out of a identifier and a integer
  followed directly by another identifier:
    #define X() X_ ## 0R()  // note: _zero_ followed by 'R'
    #define X_0R() ...
    X() // expanded to:  X_0R(), but should expand to ...
  This is a problem resulting from the fact, that the Standard requires the
  preprocessor to act on so called pp-tokens, but Wave acts on C++ tokens.

Thu Mar 20 21:39:21     2003
- Fixed a problem with expression parsing (#if/#elif constant expressions),
  which failed to produce an error message for expressions like
    #if 1 2 3 4 5
  i.e. where the token sequence starts with a valid constant expression, but
  the remainder of the line contained other tokens than whitespace.
- Integrated the flex_string class from Andrei Alexandrescu (published on the
  CUJ site) to get COW-string behaviour for the token values and position
  filename strings. This resulted in a major overall speedup (about 2-3 times
  faster in dependency of the complexity of pp usage in the input stream).
- Fixed a bug, which reported ill formed #if/#else expressions as errors, even
  if the current if block status (conditional compilation status) is false.
- Added a warning, if the last line of a file does not end with a newline.
- Improved error recognition and handling for malformed preprocessor directives

Mon Mar 17 19:53:29     2003
- Fixed a concatenation problem: constructs like a##b##c where expanded
  incorrectly.
- Optimized the recognition of pp directives:
    - the parser is used only, if the next non-whitespace token starts a pp
      directive
    - null directives now are recognized without calling the parser
    - the parser isn't called anymore, if the if_block_status is false and no
      conditional pp directive (#if etc.) is to be recognized.
  These optimizations give a speed improvement by upto 40%.
- Removed adjacent whitespace during macro expansion (needs to be revised,
  since there is some whitespace left, which may be removed)

Sun Mar 16 23:19:11     2003
- Fixed a problem with include paths given on the command line, if the file
  to preprocess was not given as a full path (driver executable).
- Fixed a problem with path names containing blanks (driver executable).
- Cleaned command line and argument handling (driver executable).
- Fixed a severe memory leak.
- Fixed a bug, if a C++ keyword was used as a macro name or macro parameter
  name, which prevented the macro recognition and expansion to function
  properly.
- Implemented the WAVE_SUPPORT_MS_EXTENSIONS compiler switch for the re2c
  generated lexer too.
- Fixed a problem, which caused an internal T_PLACEHOLDER token to show up
  outside the macro replacement engine.
- Fixed a problem with macro #include directives, which prevents to find the
  file to include, if after the macro expansion the token sequence representing
  the filename began or ended with at least one whitespace token.
- Fixed a problem, which caused a false error message if the '#' character was
  to be concatenated with an arbitrary other token.
- The concatenation of a whitespace token with an arbitrary other token was
  reported as illegal token pasting (but it is certainly not).

Sat Mar 15 21:43:56     2003
- Added a default constructor to the wave::util::file_position template.
- Report the concatenation of unrelated tokens as an error.
- Finished the documentation.

Fri Mar 14 20:14:18     2003
- More work on documentation
- Changed file_position to expose accessor functions (the member variables are
  marked as private now). This opens up the possibility to provide another
  file_position implementation, which may be optimized in some way.
- Fixed a problem with the token name table, the alternate and trigraph token
  names were printed incorrectly.
- Fixed a bug, which prevented the correct recognition of 'defined X' (without
  parenthesises).
- Fixed a bug, which allowed to redefine and undefine the predefined name
  'defined'.
- Fixed a bug, which prevents the correct recognition of a macro based #include
  directive, if it expands to something like #include <...>.
- Fixed a bug, which prevented the recognition of duplicate macro parameter
  names.
- Removed the insertion of additional whitespace inside of string literals
  (during stringizing).

Wed Mar 12 19:16:40     2003
- Fixed a bug, which prevented the instantiation of the wave::context object
  with auxiliary iterators. The token type isn't coupled anymore with the
  iterator type.
  This required some changes in the interface:
    - The wave::context object now has three template parameters (the iterator
      type, the token type and the input policy type)
    - The token type does not have the iterator type as it's template parameter
      anymore.
- Implemented a new position_iterator template on top of the iterator_adaptor<>
  template to make it work even for input_iterator type iterators.
- Fixed a bug in the regular expressions for the Slex lexer.
- The function 'set_sys_include_delimiter()' was renamed to
  'set_sysinclude_delimiter()' to better fit the naming scheme of the other
  functions.
- Wrote more documentation
- Unified the different token definitions of the lexers, so that there is only
  one token type left. This required some changes in the interface:
    - There is no need anymore to explicitly specify the namespace of the token
      type to use.
- Added the command line option -P to the Wave driver program, which predefines
  a macro (i.e. defines it such, that is _not_ undefinable through an #undef
  directive from inside the preprocessed program).

Sat Mar  8 07:46:43     2003
- Released Wave 0.9.0

Thu Mar  6 20:02:44     2003
- Compiled Wave with IntelV7.0/DinkumwareSTL (from VC6sp5)
- Fixed new compilation problems with gcc -Wall
- Fixed the list_includes and cpp_tokens samples to compile and link correctly.
- Fixed a bug, where a wrong filename was reported by the generated #line
  directive.
- Fixed a bug, where the __FILE__ macro was expanded without '\"' around the
  filename.
- The generated #line directives and the expanded __FILE__ macro now report
  the filename in a native (to the system) format. Additionally the generated
  string literals are now escaped correctly.

Wed Mar  5 21:11:14     2003
- Reorganized the directory structure to mirror the namespace structure of the
  library
- Fixed a bug, where the complete input after the first found #include
  directive were eaten up.
- Fixed a bug, where the __LINE__ macro expanded to a incorrect linenumber, if
  the __LINE__ macro was encountered on a line after a '\\' '\n' sequence.

Tue Mar  4 11:50:24     2003
- The new name of the project is 'Wave'.
- Adjusted namespaces, comments etc. to reflect the new name.
- Added the command line option -U [--undefine], which allows to remove one of
  the predefined macros (except __LINE__, __FILE__, __DATE__, __TIME__,
  __STDC__ and __cplusplus)

Sun Mar  2 20:10:04     2003
- Fixed a bug while expanding macros without any definition part (empty macros)
- The pp-iterator will not emit a newline for every recognized preprocessing
  directive anymore. The generated output is much more condensed this way.
- The pp-iterator now emits #line directives at appropriate places.
- Added an additional parser to the library, which may be used to parse macros
  given in the command line syntax, i.e. something like 'MACRO(x)=definition'.
- Added the possibility to the cpp driver sample, to add macros from the
  command line through the -D command line switch.
- Martin Wille contributed a test script to allow automatic testing of the
  cpp driver sample by feeding all files contained in the test_files directory
  through the cpp driver and comparing the generated output with the
  corresponding expectations.
- Added config file support to allow for predefined option sets (for instance
  for the emulation of other compilers)
- Changed the way, how include paths are defined. It resembles now the
  behaviour of gcc.
  Any directories specified with '-I' options before an eventually given '-I-'
  option are searched only for the case of '#include "file"', they are not
  searched for '#include <file>' directives. If additional directories are
  specified with '-I' options after a '-I-' option was given, these directories
  are searched for all '#include' directives. In addition, the '-I-' option
  inhibits the use of the current directory as the first search directory for
  '#include "file"'. Therefore, the current directory is searched only if it is
  requested explicitly with '-I.'. Specifying both '-I-' and '-I.' allows to
  control precisely which directories are searched before the current one
  and which are searched after.
- Added config file support to the cpp driver.
- stored not only the current 'name' of a file (given eventually by a #line
  directive) but in parallel the actual full file system name of this file too.

Tue Feb 25 21:44:19     2003
- Fixed the warnings emitted by gcc -Wall.
- Fixed a bug in the cpp grammar, which causes to failing the recognition of
  certain preprocessor directives if at the end of this directive were placed
  a C++ comment.
- Simplified and extended the insertion of whitespace tokens at places, where
  otherwise two adjacent tokens would form a new different token, if
  retokenized.

Mon Feb 24 19:13:46     2003
- defined() functionality was broken
- added missing typename keywords
- added missing using namespace statements, where appropriate
- added a warning, when a predefined macro is to be undefined (by an #undef
  directive)
- removed the 'compile in C mode' hack for the re2c generated lexer (VC7.1
  (final beta) is not able to compile it with optimizations switched on
  anyway :( )
- compiled with gcc 3.2 and Intel V7.0 (20030129Z)

Sun Feb 23 23:39:33  2003
- Fixed a couple of 'missing typename' bugs (thanks to Martin Wille)
- Added code to insert whitespace at places, where otherwise two adjacent
  tokens would form a new different token, if retokenized.
- Fixed a severe macro expansion bug.
- Added the handling of invalid or not allowed universal character values
  inside of string literals and character literals.

Sat Feb 22 20:52:06  2003
- Bumped version to 0.9.0
- Added test for invalid or not allowed universal character values (see
  C++ Standard 2.2.2 [lex.charset] and Annex E)
- Fixed a bug with newlines between a macro name and the opening parenthesis
  during the macro expansion and a bug with newlines inside the parameter list
  during the macro expansion.
- Added the following predefined macros:
    __SPIRIT_PP__
        expands to the version number of the pp-iterator lib (i.e. 0x0090 for
        V0.9.0)
    __SPIRIT_PP_VERSION__
        expands to the full version number of the pp-iterator lib (i.e.
        0x00900436 for V0.9.0.436)
    __SPIRIT_PP_VERSION_STR__
        expands to the full version string of the pp-iterator lib (i.e.
        "0.9.0.436")

Fri Feb 21 22:09:04  2003 (feature complete!)
- Allowed to optionally compile the Re2c generated lexer in 'C' mode, because
  at least the VC7.1 (final beta) compiler has problems to compile it in 'C++'
  mode with optimizations switch on
- Implemented #error and #warning (optional) directives (C++ standard 16.5).
  Additionally there are now allowed the following preprocessor configuration
  constants:
    CPP_PREPROCESS_ERROR_MESSAGE_BODY
        if defined, preprocesses the message body of #error and #warning
        directives to allow for better diagnostics.
    CPP_SUPPORT_WARNING_DIRECTIVE
        if defined, then the #warning directive will be recognized such, that
        a warning with the given message will be issued
- Adjusted the error handling for the Re2c generated C++ lexer, so that any
  error inside the lexer is now propagated as an cpplexer_exception.
- Implemented the #line directive (C++ standard 16.4)
- Implemented #pragma directive (C++ standard 16.6)
  Additionally there are now allowed the following preprocessor configuration
  constants:
    CPP_RETURN_PRAGMA_DIRECTIVES
        if defined, then the whole pragma directive is returned as a token
        sequence to the caller, if not defined the whole pragma directive is
        skipped
    CPP_PREPROCESS_PRAGMA_BODY
        if defined, then the #pragma body will be preprocessed
- Implemented #include directive with macro arguments (C++ standard 16.2.4)
- Made the namespace structure finer granulated to leave only the main
  interface classes in the main namespace cpp. All other classes are moved into
  sub-namespaces to reflect the logical dependencies
- Reorganized the public interface of the context<> template class, made all
  non relevant functions into the protected.
- Implemented predefined macros (__LINE__ et.al.) (C++ standard 16.8)
- Further documentation work

Wed Feb 19 23:44:47  2003
- Corrected a lot of bugs in the macro expansion engine, which now should be
  conformant to the C++ standard.
- # (null) directive (C++ standard 16.7)

Sun Feb 16 08:40:38  2003
- Added a macro expansion engine which expands macros with arguments
  C++ standard 16.3 [cpp.replace]
- Added a new sample: cpp_tokens. This sample preprocesses a given file and
  prints out the string representations of all tokens returned from the pp
  iterator
- Added documentation (to be continued!)
- Added a couple of small test files to test elementary functionality
  (the tests mainly were contributed by Paul Mensonides)
- The main cpp sample is now a simple preprocessor driver program, which
  outputs the string representation of the preprocessed input stream. Use
  cpp --help to get a hint, how to use it.
- Fixed a bug in the preprocessor grammar which failed to recognize a pp
  statement, if there was a C++ comment at the end of the line
- Added '#' operator (C++ standard 16.3.2) [cpp.stringize]
- Fixed a bug in the slex based C++ lexer to handle the concatenation
  characters correctly ('\\' followed by a '\n')

Sun Feb  9 23:01:00  2003
- Improved error handling for #if et.al.
- Fixed a pair of lexer errors
- Implemented the #if/#elif statements, the sample now contains a complete C++
  expression evaluation engine (for the calculation of the outcome of the
  #if/#elif statement conditions)
- Implemented macro replacement (with parameters)
- Implemented the '##' [cpp.concat] operator
- Implemented the defined() [cpp.cond] operator

Sun Feb  2 23:28:24  2003
- Implemented the  #define, #undef, #ifdef, #ifndef, #else and #endif
  statements
- Added optional parse tree output as xml stream (controlled through the config
  pp constant CPP_DUMP_PARSE_TREE)

Fri Jan 31 21:30:55  2003
- Fixed different minor issues and a border case (#include statement at the
  last line of a included file)

Wed Jan 29 21:13:32  2003
- Fixed exception handling to report the correct error position
- Fixed another bug in the stream position calculation scheme
- Added a more elaborate sample 'list_includes' which lists the dependency
  information for a given source file (see test/list_includes/readme.txt).

Sat Jan 18 22:01:03  2003
- Fixed a bug in the stream position calculation scheme
- Made cpp::exceptions more standard conformant (added 'throw()' at appropriate
  places)
- Overall housekeeping :-)

Wed Jan 15 21:54:20  2003
Changes since project start (still 0.5.0)
- Added #include <...> and #include "..." functionality
- pp directives are now generally recognized
- Decoupled the C++ lexers and the pp grammar to separate compilation
  units (optionally) to speed up compilation (a lot!)

Thu Jan  2 12:39:30  2003
A completely new version 0.5.0 of the C preprocessor was started. It's a
complete rewrite of the existing code base. The main differences are:
- The preprocessor is now implemented as an iterator, which returns the
  current preprocessed token from the input stream.
- The preprocessing of include files isn't implemented through recursion
  anymore. This follows directly from the first change. As a result of this
  change the internal error handling is simplified.
- The C preprocessor iterator itself is fed by a new unified C++ lexer
  iterator. BTW, this C++ lexer iterator could be used standalone and is not
  tied to the C preprocessor. There are two different C++ lexers implemented
  now, which are functionally completely identical. These expose a similar
  interface, so the C preprocessor could be used with both of them.
- The C++ lexers integrated into the C preprocessor by now are:
    Slex:   A spirit based table driven regular expression lexer (the slex
            engine originally was written by Dan Nuffer and is available as a
            separate Spirit sample).
    Re2c:   A C++ lexer generated with the help of the re2c tool. This C++
            lexer was written as a sample by Dan Nuffer too.
  It isn't hard to plug in additional different C++ lexers. There are plans to
  integrate a third one written by Juan Carlos Arevalo-Baeza, which is
  available as a Spirit sample.

-------------------------------------------------------------------------------
Tue Feb 12 22:29:50  2002
Changes from 0.2.3 to 0.2.4:
- Moved XML dumping functions to the main Spirit directory
- Fixed operator '##', it was not correctly implemented somehow :-(

Sun Feb 10 21:07:19  2002
Changes from 0.2.2 to 0.2.3:
- Implemented concatenation operator '##' (cpp.concat)
- Removed defined() functionality for Intel compiler (it ICE's) until this
  issue is resolved
- Separated code for dumping a parse tree to XML for inclusion in the main
  Spirit headers

Thu Jan 17 23:51:21  2002
Changes from 0.2.1 to 0.2.2:
- Fixes to compile with gcc 2.95.2 and gcc 3.0.2 (thanks Dan Nuffer)
- Reformatted the grammars to conform to a single formatting guideline
- Assigned explicit rule_id's to the rules of cpp_grammar, so that the
  access code to the embedded definition class is not needed anymore
- Fixed a remaining const problem

Tue Jan 15 23:40:40  2002
Changes from 0.2.0 to 0.2.1:
- Corrected handling of defined() operator
- In preprocessing conditionals undefined identifiers now correctly
  replaced by '0'
- Fixed several const problems
- Added parse_node_iterator for traversing one node in a parse_tree
  without going deeper down the hierarchy than one level (this is useful,
  if all inspected tokens arranged along a single node in the parse tree.
  The main difference to the parse_tree_iterator is, that the underlying
  iterator generally can be adjusted correctly after advancing the attached
  parse_node_iterator
- Fixed a problem with gcc 2.95.2, which doesn't have a <sstream> header
- Prepared usage of slex for lexer states

Sun Jan 13 10:21:16  2002
Changes from 0.1.0 to 0.2.0:
- Added operator 'defined()'
- Added directive '#warning'
- Corrected error reporting
- Added command line option -I- for finer control of the searched include
  directories (-I and -I- should now work as in gcc, see readme.html for
  more info)
- Corrected conditional preprocessing (should be fully functional now)
- Fixed existing code base for changes made in parse tree support
- Moved parse tree utility functions to a separate header (prepared for
  inclusion to the Spirit main library)