Re: Preprocessor suggestions

Hi,


> > I'd like to start a translator program from C to a much less
> > expressive language. My first step would be to modify the c
> > preprocessor so that it doesnt swallow up the comments.


Does doing this help or are you just trying a simple task first?


> > Anyone see a problem with trying to do this.
>
> Leaving comments in the preprocessed code is easy enough, but keeping
> comments in a parser is surprisingly tricky.


I'm not sure it was clear that comments are required in the compiler's
parser, although it's a reasonable assumption. If not, the
preprocessor could leave them in and the compiler's lexer drop them.


The C preprocessor would still need knowledge of them in macro
processing AFAICS.


        int debug_hashtable;
        int numbucket;
        int hash;


        #define DEBUG(flag, i) \
                if (debug_ ## flag) { \
                        printf("%d\n", (i)); \
                }


        void foo(void)
        {
                DEBUG(hashtable, numbucket);
                DEBUG(/* FIXME: needs its own flag. */ hashtable, hash);


                return;
        }


You wouldn't want `debug_/*' being tested in the second case.


Ralph.

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