Re: Ada.Directories

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

On Sat, 20 Oct 2007 13:35:25 -0700, Maciej Sobczak wrote:

> On 20 Pa , 21:40, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
> 
>> 2. Why Full_Name of the Directory_Entry corresponding to ".." does not
>> render the true name of? Can the same file have different full names?
>
> Of course. They are usually called "links".

"." is not a hard/soft link, as it cannot be removed. Soft links are all
determinable. Even with hard links any file system is ADG, with ". " it is
not.

> Add "mount points" and the
> game is even more funny.

These are determinable as well.

> In general, there is no such a thing as a "true name" of a file and if
> there are many there is often no way to assign different priorities
> for them.

See RM A.16 which for Containing_Directory explicitly rules that if the
file system is not a forest, then Containing_Directory still returns a
value. That in effect defines a canonic full path for any Directory_Entry.
RM also does not hesitate to order that full names of abbreviations should
be meaningful.

So I think it also should advise implementations to remove "." and ".."
mess, when possible. At least in order to honor:

Compose (Containing_Directory (X), Simple_Name (X)) = X

(It makes no sense to define Containing_Directory without keeping the file
system view forest.)

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