"Edward Diener" <[EMAIL PROTECTED]> wrote in message news:aqf73p$f9$1@;main.gmane.org... > "Paul Mensonides" <[EMAIL PROTECTED]> wrote in message > news:001601c286c9$64eedf40$6401a8c0@;c161550b... > > "Andrei Alexandrescu" <[EMAIL PROTECTED]> wrote in message > > news:aqf13l$f7e$1@;main.gmane.org... > > > A very nice Spirit code sample would be the proverbial dogfood that C++ > > eats > > > itself. To clarify: > > > > > > 1. How about an open-source C++ preprocessor (that takes care of #define > > and > > > #include) written in Spirit? Then that preprocessor could be compared > with > > > existing preprocessors in terms of speed and conformance. > > > > This one I'd like to see, but it might be too easy. There isn't much to > > Cpp. > > Having tried it many years ago in C++ using Yacc/Lex, it is not nearly as > easy as it looks. The most difficult area is macro expansion and > substitution.
It may be difficult with a framework like that, but it isn't particularly difficult doing it manually. Tokenizing is trivial, far simpler than regular C++, and the syntax for macro expansion is also very simple. The most "difficult" parsing that needs to be done is arithmetic expressions in #if/#elif directives. > The other thing to look out for, which is a non-standard > problem, is that every compiler of which I know defines their own macros > based on compiler options and programmers often use these macros to include > or not include lines of code. Finally there is the recursive inclusion of > header files, each with their own preprocessor directives. Yes. This is a problem. The only real way to handle it is to define those symbols externally so they can be setup by a user. > Of course it is much easier than the rest of the C++ language but I don't > think anyone should underestimate how difficult it might be. Don't overestimate it either. :) Of course, dealing with regular C++ on the other hand.... Paul Mensonides _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
