Re: File name completion on Mac OS X with German umlauts

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 13 Mar 2008 00:23:29 +0100
> From: "Juanma Barranquero" <lekktu@gmail.com>
> Cc: help-gnu-emacs@gnu.org
> 
> On Wed, Mar 12, 2008 at 10:55 PM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> >  In particular, I don't see why file names with "X" and "Ⅹ" are okay
> >  for you, but the two types of "ü" are not.  I think they are both
> >  exhibiting the same problem.
> 
> Well, the first two, U+0058 LATIN CAPITAL LETTER X and U+2169 ROMAN
> NUMERAL TEN, are meant to be semantically distinct.
> 
> However, U+00FC LATIN SMALL LETTER U WITH DIAERESIS is supposed to be
> semantically identical to U+0075 LATIN SMALL LETTER U plus U+0308
> COMBINING DIAERESIS. In the first case, we're talking about different
> abstract characters represented with different codepoints. In the
> second case, we're talking about the same abstract character. Other
> than a byte comparison, there is no distinction between both ü. You
> wouldn't expect a font supporting Unicode to represent U+00FC
> different that U+0075 plus U+0308.

I see no difference here: in both case the bytestreams are different.
The fact that Unicode sees one case but not the other as two
equivalent strings, is irrelevant here, because file names are not
simple text strings, they have other semantics.

Anyway, we are not talking about fonts, nor about Unicode decisions
wrt character equivalency.  We (at least I) were talking about the
``problem'' that several files have the same name if a file name is to
be interpreted as a text string.  As I said, I see no problem here,
just entrenched customs.