Re: expand-file-name leaves "/../" in expansions at times

[Miles Bader]

Chong Yidong <address@hidden> writes:
> On the other hand, I just checked, and this behavior seems to have
> been around since at least Emacs 20.  Glancing through the source
> code, this behavior seems to be deliberate---something to do with the
> "superroot directory".  Maybe someone on this list can elucidate?

I don't know anything about the Emacs code, but CMU CS had a networked
filesystem (the mach/spice project vaxes) which had the concept of a
super-root above /, accessed via "/..".  E.g. to access file "/x/y" on
machine "blargh", you'd use "/../blargh/x/y" (IIRC, "/.." was a real
directory so you could do "cd /..", "ls /.." to see all machines, etc)..

I always thought it was a rather clever idea.  It certainly messes up
assumptions some programs make, but I think the "/.." == "/" assumption
is generally rather rare in practice.  [Compare to the microsoftian "//"
superroot syntax, which messes up the far more common "//" == "/"
assumption, and just generally feels a lot more arbitrary.]

-Miles

-- 
I'd rather be consing.