[Info-vax] Why does this DIFF command fail, then run fine the 2nd time around?

[Dave Froble]

On 12/12/2022 5:24 PM, Stephen Hoffman wrote:
> On 2022-12-12 21:18:18 +0000, Dave Froble said:
>
>> On 12/12/2022 1:27 PM, Stephen Hoffman wrote:
>>> On 2022-12-12 06:45:44 +0000, alanfe... at gmail.com said:
>>>
>>>> $ DIFP SCRFELD:[.A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [.B.*]
>>>> ...
>>>> $ SHOW LOG/FUL SCRFELD
>>>> "SCRFELD" [super] = "DSA2:[USR_SCRATCH.FELDMAN.]" [concealed,terminal]
>>>> (LNM$PROCESS_TABLE)
>>>> $
>>>
>>> AFAIK, usual preferred command syntax with a concealed rooted logical name
>>> would be thus:
>>>
>>> DIFP SCRFELD:[A.TO_V530]CLEAR_NBACK_LNMS.COM;1 [B.*]
>>>
>>> Trailing dot (from the logical name, correctly) and leading dot (from the
>>> appended directory) passes along some variation of [TOS..A] and [TOS..B].
>>>
>>> Looks like a dusty corner within the name and default name and related-spec
>>> parsing, among other dusty corners within filespec parsing.
>>>
>>> Shouldn't blow up, but arguably also probably shouldn't work.
>>>
>>
>> Some people are way too fond of rooted logical names ...
>
> There are some people too fond of logical names, too.

Ayep ...

> Though this case looks more like filename parsing gone awry.

It's the other side of lots of flexibility, many options,some might claim too 
many options.

> Wouldn't be the first time there was a bug in filename parsing either, as
> somebody else (A.M.) once remarked. While debugging a parsing-related error.

The rooted logical stuff is interesting, but, sometimes just because one can do 
something, doesn't then mean that they should do it.

The early developers wanted multiple OS roots.  Ok, maybe that might be Ok.  But 
then others took the concept, and used it where it just wasn't needed.  They did 
it because they could.  Reminds me of "the road to hell is paved with good 
intentions" and other such.

> OpenVMS filename syntax is... baroque.

Don't make me look up that word ...

:-)

I have no problem with the basic filespec stuff.  I actually prefer the 
"[a.b.c]" directory specification over "/A/B/C", but I do understand the latter 
might be easier to parse.  Don't know, never used it much.  Don't like it.

> More baroque in recent years, in service to continued app compatibility.

If apps don't get "tricky" then perhaps compatibility might be easier.

> DIDing, FIDing, ^U, mount points, what's implemented in the CRTL and what's in
> the XQP, etc.

Ok, opinion time.  The CRTL should deal with C stuff.  VMS stuff has no place in 
the CRTL.  Just my opinion.  Originally VMS stuff had System Services, LIB$, 
etc.  Then someone got lazy.

-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
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