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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Command line globber/tokenizer library for C?
Date: Wed, 18 Sep 2024 06:01:33 -0700
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Xref: csiph.com comp.lang.c:388451

Michael S <already5chosen@yahoo.com> writes:

[...]

> Since I am not accustomed to the functional programming style, for
> me even a boring variant [not shown] is way too entertaining.  I
> prefer mundane (untested, could be buggy):
>
> static
> const char* collect_word(const char *s) {
>   _Bool w = 0;
>   char c;
>   while ((c = *s) != 0) {
>     if (!w && is_space(c))
>       break;
>     if (c == '"')
>       w = !w;
>     ++s;
>   }
>   return s;
> }
>
> void words_do(const char *s, Gopher go ){
>   char c;
>   while ((c = *s) != 0) {
>     if (is_space(c)) {
>       ++s;
>     } else {
>       const char *r = s;
>       s = collect_word(s);
>       go->f(go, r, s);
>     }
>   }
> }

If writing in an imperative-rather-than-functional style, I would
likely gravitate toward something like this:


   static  const char *process_word( const char *, Gopher );

   void
   words_do( const char *s, Gopher go ){
      char   c;

      while(  c = *s++  ){
         if( ! is_space(c) )  s = process_word( s-1, go );
      }
   }

   const char *
   process_word( const char *r, Gopher go ){
      const char *s = r;
      _Bool       q = 0;

      do  q ^= *s++ == '"';  while(  *s && (q || !is_space(*s))  );

      return   go->f( go, r, s ),   s;
   }


which seems to result in slightly better generated code than my
functional version, in a few spot checks using gcc or clang
under various -O settings (-Os, -O2, -O3).