pathnames

[Luca Pisati]

Alaric B. Williams wrote:
> 
> >   I highly recommend staying within the limitations of the language when
> >   designing things like pathnames. Assuming Common LISP as a reasonable
> >   base, let's go over some basics -
> 
> > Sorry, but I do only partially agree with this.
> > ANSI-CL has a reasonably good pathname design, still rooted in the
> > LispM style: host, device, directory, filename, file-extension, file
> > version. I'm often fighting with Unix because of this, since extension
> > and version have no meaning in Unix, and they are interpreted by
> > CL as "implementation specific" issues.  Probably most of
> > pathname design in CL is good, but I do not fear to have to change
> > in order to provide more independence from platform issues.
> 
> I wouldn't make versioning and extension part of the "pathname"...

Neither would I. J3X13 did ...

> I would have a type as a property of a file; on UNIX, we guess
> the type like the file command does. A resulting pathname
> object that refers to something has a method to "summon" that
> object, which locks/opens/reference counts it to delimit the
> time in which the system is using the object and it shouldn't
> be erase or anything. This method has an optional parameter to
> select a particular version, which defaults to the newest. The
> pathname object can be asked which versions of the file are
> available, with their respective modification dates, sizes,
> and other such attributes.

I agree with you.  Which means I was somehow able to
point out one weakness of ANSI CL, which assumes versioning
and extensions are something intrinsic in the concept of
pathname.  The problem I'm trying to communicate, here, is
that ANSI-CL is somehow already a virtual Lisp Env (as somebody
stated earlier on this list).  Pathnames is one example where
Lisp tried to put itself above the OS, with a dubious result.
More occurences of this half virtuality of CL will pop up
for sure later.

> ABW
> --
> Alaric B. Williams (alaric@abwillms.demon.co.uk)
> 
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