UDCs (User Defined Commands) have a default of only executing other UDCs
further down in the command list; for example:

A
echo now executing B
B
********
B
echo now executing A
A
********

Entering A at the colon prompt:

:a
this calls b
this calls a
A
Unknown command name. (CIERR 975)

Entering A at the colon prompt:

:b
this calls a
A
Unknown command name. (CIERR 975)

The creators of the UDC portion of MPE decided in their infinite wisdom,
for which we are forever thankful and in their debt, that you could
only "call forward" to prevent unwanted looping.

Later, when MPE i/X was going good, RECURSION was added because the keepers
of MPE decided it would be handy and now could trust MPE UDC command users
with this new found power [but still not set it as a default].

Even more power was available after MPE i/X was set to use script files
wherein almost anything goes.

This brings to mind a crafty System Administrator who decided that he did
not want anyone getting in on the HP3000 while he was gone for the weekend.

He set a SYSTEM wide UDC as follows:

AAAAASYSTEMEQ
OPTION LOGON,NOBREAK
BYE

Can anyone tell me why he was reloading the System Monday morning from the
Friday Night backup tape?

As for the Heinlein quote: Perhaps it is true we should be *ABLE* to do
those things, but can someone tell me why we would ever "plan an invasion"?

And one wonders whether or not to "cook a tasty meal" comes immediately
after the "pitch manure".

My preferance would be that one would wash one's hands first, but this was
not included in the list.

"analyze a new problem"... well isn't that just like a man--to want to
analyze a *NEW* problem when all the old ones haven't even been examined
yet?

Considering the state of computing in Heinlein's time, what sort of
computer do you suppose he had in mind? I believe that Grace Hopper came a
bit after his time, so he can't possibly be talking about COBOL and Visual
Basic is just not an option.

Then there is "comfort the dying"; is the hog that is dying by your hand to
be comforted during the whole ordeal?

I protest that no one could clearly define what it means to "fight
efficiently"; someone there with a stop watch to take measurements? Or
collect quantum statistics?

"Specialization is for insects"? That is certainly the management view in
which any technologist or manager should be able to be swapped with another.

As far as taking orders, I suppose that those with a PHD in certain
subjects certainly would benefit from taking orders--"Do you want that with
fries, sir?".

As for "die gallantly", it hardly makes any difference how you die--you are
dead and it makes absolutely no difference after that.

I would suppose that the gentle readers out there have already concluded
that at least I know how to pitch manure.

I will now go wash my hands.
-------------------------------------------------------------

On Thu, 16 Aug 2001 13:25:03 -0700, Tim Ericson <[log in to unmask]>
wrote:

>Mary E. Plath wrote:
>
>> I believe it is correct that UDC's can call other UDC's ?
>> Is there a limit to the number of levels of calling?
>> Does the called UDC have to be after the caller UDC
>>   in the file ?
>
>As far as that last point, see the :HELP command for the
>'OPTION' keyword - in part, it says:
>
>:HELP OPTION ALL
>       .
>       .
>       .
>    SYNTAX
>                [{LIST  }]     [{RECURSION  }]
>         OPTION [{NOLIST}] [,] [{NORECURSION}]
>       .
>       .
>       .
>    RECURSION       Specifies that the search for UDCs is to begin at
>                    the beginning of the cataloged commands list.
>                    RECURSION and NORECURSION do not have any meaning
>                    in a command file, because command files are not
>                    cataloged.
>
>HTH!
>
> +-------------------------------------------------------------------+
>  "A human being should be able to change a diaper, plan an invasion,
>  butcher a hog, conn a ship, design a building, write a sonnet,
>  balance accounts, build a wall, set a bone, comfort the dying, take
>  orders, give orders, cooperate, act alone, solve equations, analyze
>  a new problem, pitch manure, program a computer, cook a tasty meal,
>  fight efficiently, die gallantly.  Specialization is for insects."
>  -- Robert Heinlein
> +-------------------------------------------------------------------+
>  Tim Ericson       tim dot ericson     DenKor Dental Management Corp.
>  Sr. Systems Analyst    at denkor dot com      http://www.denkor.com
> +-------------------------------------------------------------------+
>
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