Re: coreutils and i18n

[Bruno Haible]

Jim Meyering wrote:
> >   - Processing in unibyte locales should not become significantly slower
> >     than before.
> >   - Code duplication should be avoided, for maintainability.
> >   - Macros which expand to one thing in the multibyte case and to another
> >     thing for the unibyte case are not acceptable.
> >
> > How will this students' project solve this dilemma?
> 
> There's no guarantee, but Paul and I will be supervising.

I mean, what is technically the solution to the dilemma? The typical idiom
for keeping the speed of the unibyte case is - see e.g. gnulib/lib/mbscasecmp.c
as an example -

  #if HAVE_MBRTOWC
    if (MB_CUR_MAX > 1)
      ... multibyte case ...
    else
  #endif
      ... unibyte case ...

but it does have code duplication.

What approach are they going after? Put a big

  switch (c)
    {
    case 'A'..'Z':
      ... handle printable ASCII characters ...
    default:
      ... handle multibyte case ...
    }

into every loop? This approach has not even sufficed for lib/mbswidth.c.

Do they want to speed up the multibyte case code by some tricks?

Or are you giving up one of the three requirements? If so, which one?

Bruno