Re: Interpretation of extensions different from Unix/Linux?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Wed, 05 Aug 2009 09:07:56 -0700, Jeffrey R. Carter wrote:

> Dmitry A. Kazakov wrote:
> 
>     a bunch of stuff
> 
> It's clear that our definitions of "neutral" differ. I mean offering a set of 
> operations common to all OS' file systems; you seem to mean offering all 
> possible operations for all OS' file systems.

Not so. The situation is same as with Ada tasks. Ada does not try to
provide all possible tasking operations, processes, threads, fibers etc.
Instead of that it provides a model of concurrent computing that can be
mapped to practically any OS. This is what I consider portable. The same
can be done to abstract file systems. We do not need to provide all
operations of concrete file systems, we have to the operation one has in
mind working with a file system.

> I don't think that a pkg meeting what seems to be your meaning is possible 
> within a reasonable effort. If you disagree, I'd like to see your version of 
> such a pkg, including implementations for 2 significantly differing file systems 
> (for example, one that maintains different versions of files and one that doesn't).

Hmm, I see no problem with that. I would change Compose, just one more
argument:

type Absolute_Path is private;
type Simple_Name is private;
type File_Extension is private;
type File_Version is range <implementation-defined>;

function Compose
(  Containing_Directory : Absolute_Path := Current_Directory;
   Name : Simple_Name;
   Extension : File_Extension := No_Extension;
   Version : File_Version := File_Version'First
) return Absolute_Path;

For a file system without versions the only valid File_Version will be 1.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de