Re: Directory listings and path names

[Brian Rogoff <bpr@bpr.best.vwh.net>]

On Sat, 19 Jan 2002, Robert A Duff wrote:
> Kilgallen@SpamCop.net (Larry Kilgallen) writes:
>
> > >> These are services of the Operating System, not of Ada (the programming
> > >> language),
> > >
> > > Says you!
>
> Well, it's true...
>
> >... I could argue the same about tasking.
>
> You can argue what you like, but it would still be false.  ;-)

I see that postmodernism and philosophical relativism have not made great
progress in c.l.a ;-)

Surely, we can find many OSes which provide no tasking, some tasking,
sophisticated tasking, etc. I subscribe to the view that what goes in
a language versus what goes in an OS is rather arbitrary. The same is
true for language and library. Library design is language design.

> > > IMO, it would be a good thing if there were some sort of standard
> > > directory package. I know, someone will argue that file systems are
> > > different. Oh yeah? So are the multitasking capabilities of various OSes.
> >
> > But a subset of multitasking capabilities has been chosen as being
> > adequate for Ada programs. Declaring a similar subset for files is
> > more difficult because files are used for communication with other
> > components of the computing environment.
>
> Nonetheless, the ARG is working on a directory operations package.

Yes, and that is a very good thing. The fact that Ada 95 did not provide
such a package has always been a bummer to me. IMO, part of the reason
Ada has failed to make a huge contribution in reusability is that it never
had the prerequisite usability. You can start with Python and immediately
use it for the mundane file munging tasks that many of us need to do,
without having to write your own bindings to the OS. Java also comes with
fairly extensive libraries for this sort of thing.

BTW, I'm speaking of Ada, not GNAT here. GNAT has had a lot of what I want
"out of the box" for a long time, but one of the supposed virtues of Ada
is supposedly portability.

> > Do I want only files that are present on the system or should shelved
> > files in that directory be included ?  How do I access only the third
> > newest version (VMS terminology - someone else can translated it into
> > partitioned data set terminology for IBM machines).

Well, the first thing you have to understand is that VMS is dead :-).

> Well, any interface-to-OS package has to be somewhat
> "least-common-denominator"-ish, if it is to be portable.

Correct. It would also be nice to provide more specific packages, like,
say, Windows, Unix/Posix, Mac (and also rans like VMS, BeOS, Amiga,... :).

-- Brian