Hi Bert,
this thread has suddenly become quite complex and sensitive. I hope that
the nuances in my reply come through.
Firstly, I did see your response about your experience on VM. I would not
expect VM to behave in the same way as Windows. The filesystem is
different. It is nearly a quarter century since I had my hands on a VM
system, but I don't remember there being a directory structure at all just
filename filetype and Disk[mode] - perhaps I'm remembering wrong.
Secondly, the code as you posted it doesn't demonstrate how the directory
function actually behaved at that time, in fact, reading your post I can't
even be certain of how you expected it to behave. I read several
possibilities into this scenario, including one where the documentation was
just as ambiguous then, and the interpreter writers intention was the same
then as the observed behaviour today.
You say "all implementations of the language should match" and you go on to
establish a principle of prior precedent. Now I don't know what you mean
by 'should', I would agree that *gratuitous* change should be avoided. I
think that the reason that this is desirable is not because the language
needs to be fixed in stone, but because changes cause programs out there to
break.
I don't know how the directory BIF worked on Object Rexx for OS/2 or the
system interpeter on VM, but I have verified to my satisfaction by looking
at the code in the ooRexx repository that the current behaviour has been
present on ooRexx for Windows and Linux for at least the last eight years,
and possibly more.
I don't know how other interpreters work - although looking at the manuals
I have for Personal Rexx & Kexx I see that they each handle this very
differently. Regina appears to have a directory BIF for OS/2 only and the
helpfile seems to indicate that the behaviour in Regina for OS/2 is exactly
the same as what happens in ooRexx currently. I hope Mark doesn't mind,
but I quote the Regina OS/2 help below.
Now, given that it isn't possible to have all rexx interpreters working
exactly the same, because we see such a spread of behaviour, and that the
current behaviour in ooRexx for Windows and Linux has been in place for a
long time, I would say that changing this behaviour to match some behaviour
that might have existed on some interpreter on some platform in the past
would break more currently active code than recognising that this change
may have occurred in the past and that the helpfile is ambiguous and
correcting the helpfile suitably.
I hope that that makes my position on this clear. Sorry if it opens a can
of worms.
Jon
Regina's Directory BIF for OS/2 helpfile:
> DIRECTORY([new directory]) - (OS/2)
> Returns the current directory for the running process, and optionally
> changes directory to the specified new directory. If the new directory
> exists, and the change to new directory succeeds, the new directory is
> returned. If the new directory does not exist or an error occurred changing
> to that new directory, the empty string is returned.
On 4 February 2016 at 02:03, Bertram Moshier <bertrammosh...@gmail.com>
wrote:
> Hi Jon,
>
> .
>> I would say that this is a documentation bug as the documentation lists
>> two different behaviours which can't both be right, and the code only
>> displays one of these behaviors.
>
>
> I think my earlier email about find a VM/CMS example went though, but in
> case it didn't (I sent it from a tablet). I found an example in my old
> notes, while at Cray Research, Inc, of using it as:
>
> Current_Dir = directory(New_Dir) where New_Dir was a valid location.
>
> I also think I successfully used this coding using classic Rexx under OS/2
> Warp, but have yet to find my old OS/2 Warp drives.
>
> As all implementations of the language should match and VM/CMS, OS/2 Warp,
> MVS, etc all came earlier, I'd say the documentation and code both are off
> in their own ways. The documentation needs to be clear, obviously. Also
> the implementation should allow functions, such as the directory, to
> function the same regardless.
>
> Would this be two bug reports or one for two areas?
>
> Bert.
>
>
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