Topic: Parented BBoard/Intercom
Author: Trispis
Summary: Commands and information can be shared among many objects without
duplication, thus reducing database space consumption. In this log, Trispis
walks a player through the creation of an intercom messaging system.

Log file from M*U*S*H.

6/23/98 7:54:18 PM

<Code> Xira says, "done (not logging to beginning)"

<Code> Trispis nods.
<Code> Trispis says, "Okay..."
<Code> Trispis says, "Let's work with the bbs (message storage/retrieval)
only..."
<Code> Trispis says, "You want objects in specific locations which access a
common set of messages. Right?"

<Code> Xira says, "yes."

<Code> Trispis says, "Do you wish to set any sort of limit on how many
messages can be stored?"

<Code> Xira says, "well, actually, perhaps after so many are stored it starts
to delete the oldest"

<Code> Trispis says, "Okay. Good. That simplifies things."
<Code> Trispis says, "What we can do is make one object... which stores and
displays messages. Then, make several other objects which are parented to that
object (reducing code and thus dbspace)."
<Code> Trispis says, "So... we'll begin with /one/ object.... and get it
working."

<Code> Xira says, "okay."

<Code> Trispis says, "You really only need to do two basic commands for this
(write and read, or whatever). And one bit of message counting to keep track
of the messages."
<Code> Trispis says, "Let's begin by setting our limit (which we can change at
any time later) to 5 messages (remmber, we can change this later, but 5 is
easy to fill up and test our rollover when we're debugging)."

<Code> Trispis says, "That's about all the planning we can do before we
actually start writing some code (lest we start forgetting what we're
planning)."
<Code> Trispis says, "So... you need to create your first object..."

<Code> Xira says, "Bulletin Board DB?"

<Code> Trispis says, "That's fine, or BB Parent (since that's what it'll
become)."

Created: Object #2329.

<Code> Trispis says, "It's really irrelevant what you name it, cuz I'll be
referring to it's #dbref after you make it. (:"

<Code> Xira says, "created, #2329"

<Code> Trispis says, "Okay."
<Code> Trispis says, "do this..."
<Code> Trispis says, "&msg.limit #2329=5"

BB Parent/MSG.LIMIT - Set.

<Code> Trispis says, "Then, do this..."
<Code> Trispis says, "&current.msg #2329=1"

BB Parent/CURRENT.MSG - Set.

<Code> Xira says, "done."

<Code> Trispis says, "Okay... Now, I /could/ have you go ahead and make five
empty messages on there, but it's not necessary... the code we'll make will do
this as needed."
<Code> Trispis says, "Next, we need to make a command for 'writing' messages
(later, we'll make ones to read them)."
<Code> Trispis says, "So... do this...

&cmd.write #2329=$write *:&msg.[u(#2329/current.msg)] #2329=%0;@set
#2329=current.msg:[switch(u(#2329/current.msg),5,1,inc(u(#2329/current.msg)))]
"

...Pretend that's all on one line."

BB Parent/CMD.WRITE - Set.

<Code> Xira says, "set."

<Code> Trispis cools.

<Code> Xira says, "wait a sec, explain some of this to me."

<Code> Trispis nods.
<Code> Trispis says, "What it does is this..."

<Code> Trispis says, "You use the command: write <message> ... and it stores
<message> in an attribute named MSG.<current.msg>"

<Code> Trispis says, "Then..."

<Code> Trispis says, "It resets the value stored in CURRENT.MSG ... depending
on what its current value is. If it's 5 (the limit), it resets it to 1.
Otherwise, it increments it by one (current value plus 1)."

<Code> Xira says, "what is %0?"

<Code> Trispis says, "It's the * in the command portion ($write *)"

<Code> Xira says, "i didn't think it was what i thought it was (that didn't
make sense)"
<Code> Xira says, "okay."

<Code> Trispis says, "That's pretty much all that's necessary for message
storage."
<Code> Trispis says, "The next thing we need is message retrieval (reading)."
<Code> Trispis says, "So, do this...

&cmd.read #2329=$read
*:[ifelse(and(isnum(%0),member(lnum(1,u(msg.limit)),%0)),
pemit(%#,u(msg.[%0])),pemit(%#,Invalid input.)]"

...Once again, pretend that was all one line."

<Code> Xira says, "another question, what are the 'u's for?"

<Code> Trispis says, "they're a short form of ufun() (They're covered in the
ClassLog2.txt)."

<Code> Xira says, "okay, i will run though it."

<Code> Trispis says, "Now..."
<Code> Trispis says, "@set #2329=!no_command"

Flag reset.

<Code> Xira says, "know what it does, no explanation."

<Code> Trispis says, "Now do the following 5 commands..."

<Code> Trispis says, "

write Test message number one.

write Test message number two.

write Test message number three.

write Test message number four.

write Test message number five.

"

<Code> Xira says, "should i drop it first?"

<Code> Trispis says, "Not necessary."

<Code> Trispis says, "Just be sure to do all five of those."

<Code> Xira says, "how come i get no message when i type something (did we
forget a @emit?)"

<Code> Trispis says, "Those are just fancy frills to be added later."
<Code> Trispis says, "Okay... I see you're done."

<Code> Xira says, "okay, i usually put them in to reassure myself."

<Code> Trispis says, "Now... do this..."

<Code> Trispis says, "write Test message number six."

BB Parent(#2329)
Type: Thing Flags:
Owner: Xira Zone: *NOTHING* Ducats: 1
Parent: *NOTHING*
Powers:
Warnings checked: none
Created: Tue Jun 23 20:11:39 1998
Last Modification: Tue Jun 23 20:36:22 1998

MSG.5 [#2362$]: Test message number five.
MSG.4 [#2362$]: Test message number four.
MSG.3 [#2362$]: Test message number three.
MSG.2 [#2362$]: Test message number two.
MSG.1 [#2362$]: Test message number six.

CMD.READ [#2362]: $read
*:[ifelse(and(isnum(%0),member(lnum(1,u(msg.limit)),%0)),pemit(%#,u(msg.[%0]))
,pemit(%#,Invalid input.)]

CMD.WRITE [#2362]: $write *:&msg.[u(#2329/current.msg)] #2329=%0;@set
#2329=current.msg:[switch(u(#2329/current..msg),5,1,inc(u(#2329/current.msg)))
]

CURRENT.MSG [#2362]: 2

MSG.LIMIT [#2362]: 5

Home: Omphalos Park(#0RtJN)
Location: Xira(#2362PenAC)

<Code> Xira says, "neat."

<Code> Trispis says, "Okay... writing works."

<Code> Trispis says, "Now try reading a few: read 1 or read 2 or whatever (1-5
are valid numbers)."

Test message number six.

Test message number three.

Test message number two.

<Code> Xira says, "okay, and it throws one, out. That works."

<Code> Trispis says, "It does what?"

<Code> Xira says, "throws the first message out"

<Code> Trispis says, "Right... it just goes back and replaces the oldest with
the newest."

<Code> Xira says, "what about replies and stuff?"

<Code> Trispis erms.

<Code> Trispis isn't about to try to write a message threader. What you have
works as a single object. Our next step is to make it work as a parent (which
it should do automatically after we parent a few objects to it).
<Code> Trispis is working on functionality at the moment.
<Code> Trispis is also running out of time...

<Code> Xira says, "running out? got a date?"
<Code> Xira says, "we can work on this tomorrow."

<Code> Xira says, "a bulletin Board Relay system kinda thing."

<Code> Trispis figures other people can probably help you with frills later.
However. I want to get the parenting done first.
<Code> Trispis says, "So... do this..."
<Code> Trispis says, "@set #2329=no_command"

Flag set.

<Code> Trispis says, "@create BB Child"

Created: Object #2359.

<Code> Trispis says, "@parent BB Child=#2329"

<Code> Trispis says, "@set bb child=!no_command."

Parent changed.

Flag reset.

<Code> Trispis says, "Then, do the write command again (continuing with seven,
eight, etc.) about 3 or 4 times."
<Code> Trispis says, "eg: write Test message number seven."
<Code> Trispis says, "It works. (:"
<Code> Trispis says, "You can now parent as many objects as you'd like to
#2329 and they'll all use the same five messages."

BB Parent(#2329n)
Type: Thing Flags: NO_COMMAND
Owner: Xira Zone: *NOTHING* Ducats: 1
Parent: *NOTHING*
Powers:
Warnings checked: none
Created: Tue Jun 23 20:11:39 1998
Last Modification: Tue Jun 23 20:43:50 1998

MSG.5 [#2362$]: test message number 10
MSG.4 [#2362$]: test message number nine
MSG.3 [#2362$]: test message number eight
MSG.2 [#2362$]: test message number seven
MSG.1 [#2362$]: Test message number six.

CMD.READ [#2362]: $read
*:[ifelse(and(isnum(%0),member(lnum(1,u(msg.limit)),%0)),pemit(%#,u(msg.[%0]))
,pemit(%#,Invalid input.)]

CMD.WRITE [#2362]: $write *:&msg.[u(#2329/current.msg)] #2329=%0;@set
#2329=current.msg:[switch(u(#2329/current.msg),5,1,inc(u(#2329/current.msg)))]

CURRENT.MSG [#2362]: 1

MSG.LIMIT [#2362]: 5

Home: Omphalos Park(#0RtJN)
Location: Xira(#2362PenAC)

<Code> Trispis says, "If you want to save more messages, just change msg.limit
to higher number."

<Code> Xira says, "and they all read/write off the parent?"

<Code> Trispis nods. That's right. (:
<Code> Trispis has to bail.