I think the best soulution would be like you suggested to add the '$' character to the valid basic source character set to allow identifiers containeing a $. I therefore tested out how different major compilers and versions of these compilers handle this. The following compilers and versions of the compilers allow a '$' character within the identifiers (of macros): gcc 2.95, 3.1, 3.2, 3.3.3, 3.4.3 and 4.0.2 icc (intel c compiler) 8.0, 8.1 I would corroborate for the fact that it seems like there is some traction for allowing '$' characters within identifiers in major compiler preprocessors. I have not been able to reproduce the error you got with GCC or with any other compiler . Which compiler and version did you use when you got your error message? Thanks Andreas On 11/18/05, Hartmut Kaiser <hartmut.kaiser@gmail.com> wrote:
Andreas Sæbjørnsen wrote:
When preprocessing the code #define $jack int test; $jack using any preprocessor using the wave library, in this case the samples/lexed_tokens/lexed_tokens preprocessor , gives the following error:
PP_DEFINE (#369) at test.C ( 1/ 1): >#define< SPACE (#393) at test.C ( 1/ 8): > < lexed_tokens: /home/saebjornsen1/projects/boost/boost/wave/token_ids.hpp:497 : boost::wave::util::flex_string<char, std::char_traits<char>, std::allocator<char>, boost::wave::util::CowString<boost::wave::util::AllocatorStrin gStorage<char, std::allocator<char> >, char*> > boost::wave::get_token_name(boost::wave::token_id): Assertion `id < T_LAST_TOKEN-T_FIRST_TOKEN' failed. Aborted
using the preprocesor cpp (from the gcc team) I get (as cpp test.C): # 1 "test.C" # 1 "<built-in>" # 1 "<command line>" # 1 "test.C"
int test;
I believe the problem lies in that the lexer does not recognize the '$' as a valid character within the name of macro definition.
Accordingly to the Standard the '$' character is _not_ part of the basic source character set (see 2.2.1 [lex.charset]). For this reason it won't get recognized as the part of a identifier.
I fixed the lexed_tokens sample (actually the Wave library) so you won't get an assertion anymore, but a meaningful output. Now the output is:
PP_DEFINE (#369) at test.cpp ( 1/ 1): >#define< SPACE (#393) at test.cpp ( 1/ 8): > < <UnknownToken> (#36 ) at test.cpp ( 1/ 9): >$< IDENTIFIER (#381) at test.cpp ( 1/10): >jack< SPACE (#393) at test.cpp ( 1/14): > < INT (#335) at test.cpp ( 1/15): >int< SPACE (#393) at test.cpp ( 1/18): > < IDENTIFIER (#381) at test.cpp ( 1/19): >test< SEMICOLON (#297) at test.cpp ( 1/23): >;< NEWLINE (#395) at test.cpp ( 1/24): >\n< NEWLINE (#395) at test.cpp ( 2/ 1): >\n< <UnknownToken> (#36 ) at test.cpp ( 3/ 1): >$< IDENTIFIER (#381) at test.cpp ( 3/ 2): >jack< NEWLINE (#395) at test.cpp ( 3/ 6): >\n<
BTW: when using the wave driver for the code given above you get:
test.cpp(1): error: ill formed preprocessor directive: #define
What certainly could be done additionally is to add the '$' character to the valid basic source character set to allow identifiers conatining a '$', but this weakens the Standards conformance of Wave. Any suggestions?
HTH Regards Hartmut
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