Re: HowTo: directory-files and friends and case-insensitive match

[raman]

Eli Zaretskii <address@hidden> writes:
You understood the question correctly.

I'm specifically trying to match file extensions in a case insensitive
manner in this instance, so yes a somewhat more confined problem.  Given
the complexity I'll just go ahead and construct the regexp to match
lower and upper case.
>> From: raman <address@hidden>
>> Date: Fri, 05 Feb 2016 19:40:10 -0800
>> 
>> At present there is no obvious means to make directory-files and friends
>> match files in a case-insensitive manner -- is there a trick I'm
>> missing, or is this a missing feature?
>
> What do you mean by "match files"?  directory-files doesn't match any
> files, unless its 3rd argument is a regexp.  If you meant matching
> against that regexp, then indeed currently you cannot specify
> case-insensitive matches.  The matching is always case-insensitive on
> MS-Windows, and always case-sensitive on all other platforms.
>
> Technically, this is easy to change, but note the 2 fundamental
> difficulties with doing that:
>
>   . It is not clear which case mapping to use.  We have a case mapping
>     set up for each buffer, but using that for file names sounds
>     questionable.  We could set up a special case mapping for file
>     names, but we need to figure out what language to base that on.
>     (The MS-Windows code mentioned above uses a kludge which I don't
>     think we should keep if we make this a user-visible feature.)
>
>   . directory-files etc. should be able to (and do in practice) work
>     with unibyte file names in certain situations.  Emacs doesn't know
>     how to downcase unibyte characters.
>
> So this is a small project, actually.  Volunteers are welcome.
>

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