----- clip -----
returns the current directory, first changing it to NewDirectory if an
argument is supplied and the named directory exists. If NewDirectory is not
specified, the name of the current directory is returned. Otherwise, an
attempt is made to change to the specified NewDirectory. If successful, the
name of the NewDirectory is returned; if an error occurred, null is
returned.
----- eclip -----
Yes, I agree the text you found is clearer.
Jon
On 4 February 2016 at 15:42, Les Koehler <vmr...@tampabay.rr.com> wrote:
> I find the Regina OS/2 Help just as confusing! First, it starts with a
> simple declarative and non-contradictory sentence:
>
> ----- clip -----
> Returns the current directory for the running process, and optionally
> changes directory to the specified new directory.
> ----- eclip -----
>
> I've seen this technique in ooRexx before and it's quite logical. It
> provides, in one operation, the name of the directory to restore *and*
> switches to the new (presumably valid) directory. Neat!
>
> However, the sentences that follow *modify* the previous declarative
> sentence, thus creating confusion:
>
> ----- clip -----
> 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.
> ----- eclip -----
>
> The original Object Rexx Beta Draft was much clearer:
>
> ----- clip -----
> returns the current directory, first changing it to NewDirectory if an
> argument is supplied and the named directory exists. If NewDirectory is not
> specified, the name of the current directory is returned. Otherwise, an
> attempt is made to change to the specified NewDirectory. If successful, the
> name of the NewDirectory is returned; if an error occurred, null is
> returned.
> ----- eclip -----
>
> Maybe its just me, but this is a prime example of non-professional writers
> trying to *improve* what an expert writer wrote to begin with! Generally
> speaking, we should guard against such changes.
>
> Les
>
>
>
> On 2/4/2016 2:59 AM, Jon Wolfers wrote:
>
>> 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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