Re: shell variable namespaces

[Jim Meyering]

Bruno Haible <address@hidden> wrote:
> Jim Meyering wrote:
>> I see that there are many other uses of "$result" in that file.
>> How about using a name that doesn't impinge on the configure.ac
>> writer's name space?  E.g., s/result/gl_result/g in stdint.m4
>
> There are many more shell variables used in macros that don't have a
> particular prefix.
>
> acl.m4                  use_acl
> csharpcomp.m4           error
> eoverflow.m4            have_eoverflow
> gc.m4                   libgcrypt
> gettext.m4              is_woe32dll
> host-os.m4              os
> intdiv0.m4              value
> javacomp.m4             source_version target_version goodcode failcode \
>                         cfversion
> lib-link.m4             with_gnu_ld wl libext shlibext \
>                         hardcode_libdir_flag_spec hardcode_libdir_separator \
>                         hardcode_direct hardcode_minus_L enable_rpath \
>                         use_additional additional_includedir \
>                         additional_libdir rpathdirs ltrpathdirs \
>                         names_already_handled names_next_round \
>                         names_this_round already_handled uppername value \
>                         found_dir found_la found_so found_a haveit basedir \
>                         dir alldirs next
> lib-prefix.m4           searchpath
> ls-mntd-fs.m4           getfsstat_includes
> nanosleep.m4            nanosleep_save_libs
> perl.m4                 candidate_perl_names perl_specified found
> po.m4                   srcdirpre useit desiredlanguages lang frobbedlang \
>                         presentlang
> ptrdiff_max.m4          result
> signalblocking.m4       signals_not_posix
> size_max.m4             result
> stdint.m4               result

Thanks for identifying those.

> 1) Do you think it's worth to change them all? Did you experience a
>    collision between your variables in configure.ac and one in *.m4?

Yes, I have experienced collisions (though none recently).  That's why I
brought it up.  They are far more likely with short and generic names like
$found, $result and $dir.  Although I wouldn't worry about the long ones,
it would be nice to rename them use a prefix, too.

> 2) When using such namespaces, moving macros from/to gnulib needs renamings.
>    Unnecessary diffs.

IMHO, the important thing is that there be *some* prefix.
Having a mix of e.g., gl_ and gt_ prefixes shouldn't cause trouble.