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

[Stephen Hoffman]

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.

Though this case looks more like filename parsing gone awry.

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.

OpenVMS filename syntax is... baroque.

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

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

And in the current (2019) doc, UTF-8 / UCS-2 doc is ~missing, the 
"^UP^" POSIX stuff is seemingly missing, and there's a section 
"Information about Unicode TBS".

The more I know about the filename parsing and character encoding in 
this context, and how logical names fit in, the less I understand about 
it all...

All that before discussions of normalizing a filenames, something that 
does not (yet?) exist.


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