RE: [clisp-list] make-pathname; directory components

[John W. <wi...@in...>]

> > :up in a directory component:
> >
> >   [21]> (make-pathname :directory '(:relative "DPMA" :up "DPMA"))
> >
> >   *** - MAKE-PATHNAME: illegal :DIRECTORY argument (:RELATIVE "DPMA" :UP
> > "DPMA")
> >
> > (I guess this one isn't required to work by the standard, but it would
> > sure be nice.)
>
> why?  how is :up better than ".."?

Well, the standard does explicitly mention the use of the :WILD,
:WILD-INFERIORS, :UP, and :BACK "special markers" inside directory
components, and what each symbol means.  If you're going to support
the functionality, which does seem useful, I think it's best to go
with the standard way of implementing it.

When I said that the standard didn't require these to work, I was
referring to the part that says

  Supplying any non-string, including any of the symbols listed below,
  to a file system for which it does not make sense signals an error
  of type file-error. For example, Unix does not support
  :wild-inferiors in most implementations.

And ".." at least could be a problem in a filesystem that allows files
to be named ".." (like the Macintosh?  I know MCL understands :UP but
I don't remember its namestrings ever containing "..").


John Wiseman