Copyright 1988-2016 by Kevin G. Barkes

All rights reserved. This article may be duplicated or
redistributed provided no alterations of any kind are
made to this file.

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DCL DIALOGUE

Originally Published March, 1988

By Kevin G. Barkes

Cookies for the Masses

As an independent consultant, you never know what type of
challenges await you. Clients want the darndest things.

One of them asked for a DCL-based fortune cookie program. 
He was tiring of the messages in his current public-domain
COOKIE, but as a MicroVAX user in an office environment, he
had no "languages" available to him except DCL.

Charging a client to produce something this "frivolous" was
a bit distressing to me, so I produced it on my own time,
made it public domain, and stuck it out on my BBS system
where it can be freely copied and distributed. It's on ARIS
now, too, so feel free to download it and have fun.

The Concept:

A fortune cookie program produces a random qutotation when
invoked. This posed two interesting problems for the DCL
version; how to store the quotations, and how to access them
in a random manner.

I dismissed the use of indexed files because of their
susceptibility to damage; I had visions of getting all sorts
of calls when unwitting users edited the indexed quote file
with a text editor and totally whacked the file structure. 
Of course, the same thing is possible if the library file is
edited, but a user is more likely to recognize a VMS file in
text library format to be something other than a normal
file.

I settled on using a text library, with module names being
simply numbers; 1, 2, 3, etc. The module would be called by
the randomly-generated number.

Using lexical functions, I generated the library module
number by extracting the "ones" and hundredths seconds
fields of the current time. This approach permits modules
numbered from 0 to 999, or 1,000 possible quotes.

BAKE.COM:

Cookies have to be prepared before being consumed, and the
DCL variety is no different. BAKE.COM reads in a plain text
file containing the quotes and produces a text library.

To run BAKE.COM, you need to do three things: assign the
name COOKIE_JAR to the file which will contain the library;
assign the name OLDCOOKIES to the file where old COOKIE_JARs
will be copied; and be certain the quote file, COOKIE.IN,
exists in the directory where BAKE.COM is invoked. Make
certain to give full file specifications (device, directory,
name and extension) to the files.

COOKIE.IN, the quote file, requires no special formatting. 
Just be certain that blanks lines separate each quote.

When invoked, BAKE.COM sets up its environmental conditions
and checks for the existence of needed files. The present
cookie library is copied to another file for safekeeping,
and is then deleted.

BAKE reads COOKIE.IN, generates temporary files one at a
time, assigns them numerical module numbers, and adds them
to the text library file.

This is not a particularly efficient procedure, but its
infrequent use did not warrant spending an enormous amount
of time on optimization. Besides, the price is right
(grin).

COOKIE.COM:

COOKIE extracts a quote from the library and displays it on
the user's terminal.

If it can't find the "cookie jar", it exits immediately. 
Otherwise, it generates its "random" number, and tries to
pull a quote from the library.

This method has one major drawback... what if the cookie jar
has less than 1,000 quotes or, somehow, a gap exists in the
module numbers? COOKIE circumvents this problem by checking
the status of the LIBRARY/EXTRACT command. If it fails, it
divides the COOKIE number by two and trying again; it will
continue to do this for five iterations, then give up.

For example, assume the random number generated is 840. You
don't have 840 quotes in your library; the extract fails. 
COOKIE divides 840 by 2, producing 420, 210, 105, 52 and 26
before giving up.

You can make COOKIE run faster by dividing by a larger
number (3 or 4 are probably more efficient). You can also
increase the size of your library by duplicating entries if
you're short on pithy sayings.

******

The months ahead will feature some nifty user-submitted
procedures. If you'd like to join in the fun, feel free to
send your submissions to me at the address above or to the
DEC Pro's main office. We prefer submissions on magtape,
since we don't have the time to rekey all the material we
get.

And please... no more default-changing command files. I
received a letter from a reader who boasted the ultimate
utility, requiring only a single parameter in order to
operate. The command file:

$ SET DEFAULT 'P1'
$ EXIT

Easy to debug, and it works!


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Kevin G. Barkes is an independent consultant. He publishes
the KGB Report newsletter, operates the www.kgbreport.com website,
lurks on comp.os.vms, and can be reached at kgbarkes@gmail.com.