Re: file-readable-p returns t for empty string

[David Kastrup]

eliz@is.elta.co.il (Eli Zaretskii) writes:

> On 28 Feb 2002, David Kastrup wrote:
> 
> > > Do you mean, return ""?
> > 
> > Yes.
> > 
> > > That would violate the principle that expand-file-name always
> > > returns an absolute file name.
> > 
> > Absolute file names come in a variety of flavours.  They do not need
> > to start with "/".  For example, there are systems where they start
> > with the equivalent of "C:" before the first root /, or even
> > "/ftp@ftp.gnu.org:".  So what is it that qualifies an absolute file
> > name?

[you snipped: my contention that it shoud behave the same regardless
of the current work directory]

> See file-name-absolute-p.  It says that in Emacs, a file name is absolute 
> if it satisfies one of these conditions:
> 
>   - begins with a directory separator (normally `/')
> 
>   - begins with a `~'
> 
>   - on DOS/Windows systems begins with a drive letter

Well, I doubt we have many programs that do the equivalent of
(while (not (file-name-absolute-p file))
        (setq file (expand-file-name file)))

Even if one did, file-name-absolute-p is highly system dependent.
One could make it return t for "" as well if one was so inclined.  I
rather doubt that applications rely on certain semantics of
file-name-absolute-p for illegal file names.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum
Email: David.Kastrup@t-online.de