image 1


in your own time…

Copyright © 1995, 1998, 2012 Jerry Stratton

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3, published by the Free Software Foundation. A copy of the license is included in the section entitled “GNU Free Documentation License”.

image 2 October 4, 2011


Getting To Valhalla

Valhalla used to be on a computer at the University of San Diego. It no longer exists. But this document will still be useful for beginners to MOO.


In order to get to a “MOO”, you need a “MOO Client”, just like you need a web client to get to the web, or an e-mail client to get e-mail. If you don’t have a MOO client, don’t panic: you can use any old telnet program at first.

You also need to know the “host” and the “port” of the MOO you want to get to. For example, if the MOO says to use the host, and port 4444, you would ‘telnet’ to:

telnet 4444

Note that Valhalla MOO isn’t actually running right now: it only runs when I have need of it. But I’ll be using it for examples because it’s the one I use most often.

Getting Into Valhalla

When you arrive at Garm’s cave, you’ll type

@connect your-player your-password

to get past the cute little puppy. If you don't have a player yet, you'll need to create one, by thinking up a name and password, and typing:

@create your-player-name your-password

Valhalla will tell you if the player name you've chosen is already being used. You'll then have to use @create with a new name. Once you're in Valhalla, type


to see the latest edition of the Valhalla News-Rune, for the latest information about Valhalla and the people who use it.

Getting Around

When you want to see what’s around you, type


and type

look object

to look at a particular object. For example, try:

look me

Whenever you say me, Valhalla assumes you’re talking about yourself.

Usually, there will be some directions you can go, such as north, door, or docks. Type

go place

to go somewhere. Look in the description of where you are to see possible directions to go in. You can also get a ‘compass rose’ by typing @rose.

If you have a home, you can type


and you’ll be transported there just like in the Wizard of Oz.

You can get help by typing help. You can get help on a topic by typing help topic. We have no psychiatrists in Valhalla. Yet.

Virtual Self

You are malleable. You yam what you yam and you ain’t no more. When you first use your player, you will have something like the following generic description:

look me

You see a player who should type '@describe me as ...'.

It is awake and looks alert.

You can describe things that you own (and you own yourself) with the command:

@describe object as "Description"

You’ll also need to set your gender if you are male or female.

For example:

@describe me as "Loki, half-giant, half-Aesir, is a dashing fellow with a sly smile."

@gender male

The next time someone looks at you, they’ll see:

look me

Loki, half-giant, half-Aesir, is a dashing fellow with a sly smile.

He is awake and looks alert.

You are ‘awake’ because you are here. When you leave Valhalla you are asleep. You are ‘alert’ because you are doing something. If you leave your player unattended for a while, you are staring off into space.

Interacting With Other People

The most common ways of interacting with other people are by ‘talking’, ‘emoting’, and ‘paging’.

"Hi everybody! Where's the ale?

You say, "Hi everybody! Where's the ale?"


Balder smiles.

:chugs a tanker of ale.

Balder chugs a tanker of ale.

page Thor "Hey, Thor, there's a great party over at the circus.

Your message has been sent.

Meanwhile, Thor sees:

You sense that Balder is looking for you in The Fields of Valhalla.

He pages, "Hey, Thor, there's a great party over at the circus."


"Hi everybody! Where's the ale?

First, I talked. To talk, you type a quotation mark (double-quote) and what you want to say. Everyone else sees:

Balder says, "Hi everybody! Where's the ale?"



Then, I emoted. This uses the colon. Everyone else saw:

Balder smiles.

The ‘emote’ can be used to do things as well. For example, chugging a tanker of ale. There's a difference, however, between chugging a tanker of ale by emoting, and chugging an actual tanker of ale. To really chug a tanker (and what does ‘really’ mean in a virtual reality?), you need to have an object called tanker, and this object must contain a verb called chug. More about objects and verbs later, though.


When you talk, only the people who are in the same room can hear you. If there’s someone else in Valhalla, you can page them.

The syntax is:

page player "text of page

For example:

page Thor "Hey, Thor, there's a great party over at the circus.

Thor sees:

You sense that Balder is looking for you in Balder's Chimney.

He pages, " Hey, Thor, there's a great party over at the circus."

To find out who is awake in Valhalla, type


Player name Connected Idle time Location

Balder (#78) an hour 0 seconds The Fields of Valhalla

Loki (#79) 20 minutes 10 minutes Jotunheim

Thor (#3) 2 hours 10 seconds Bifrost Bridge


You can also whisper to someone if you want to have a private conversation without finding an empty room.

whisper "What's with the funny hat?" to Thor

You whisper, "What's with the funny hat?" to Thor.

And, Thor sees:

Balder whispers, "What's with the funny hat?"

Nobody else in the room sees anything at all.


You can send and receive mail within Valhalla. You send mail with the @send command. You’ll be asked for a subject, and then you can type in your message, one line at a time.

@send Fred


[Type a line of input or `@abort' to abort the command.]

Party at Thor's

Mail Room

Do a 'look' to get the list of commands, or 'help' for assistance.

Composing a letter to Balder (#78) entitled "Hello, Fred."

"There is a party at Thor's on Tuesday night, 7:30 pm Valhalla time.

Line 1 added.

"Can you bring your keg-of-20-drinks?

Line 2 added.

Note that you have to use a quotation mark, as if you are saying something, to add text. That's because you are saying it, and the ‘Mail Room’ is dutifully writing down what you say.

If you want to see what you’ve typed so far, you can use list.


1: There is a party at Thor's on Tuesday night, 7:30 pm Valhalla time.

2: Can you bring your keg-of-20-drinks?

To change something you’ve written, use subst (for substitute). The syntax is subst /text-as-it-is/text-as-you-want-it/lines-the-text-is-in. For example,

sub /your/my/2

2: Can you bring my keg-of-20-drinks?

changes the your in line 2 to my. You can also specify a range of lines, for example, 2-5. If you don’t know what the last line is, you can use the dollar sign $. Valhalla interprets $ as ‘the end’.

Use send when you’re ready to send the message on its way. If you change your mind and decide not to send any mail, use abort.



Mail actually sent to Fred (#99)


The stone chimney is smokey and warm, and a bit cramped for anyone of normal size. Dirty elfs skitter about as they see you coming.

You see the Chimney description again because, when you are composing a mail message, you are actually in a different room—the ‘Mail Room’. After you ‘send’ the message, you return to wherever you were before composing the message.

When Fred receives the message, he sees:

You have new mail (1) from Balder (#78).

Type `help mail' for info on reading it.

You can list your mail by typing:

@mail on me

1:+ Jul 15 11:37 Fred (#99) Re: Hello, Fred.

2:+ Jul 15 12:59 Thor (#3) Party Canceled


You can read a message by typing

@read # on me

where # is the number of the message you want to read. Delete a message with

@rmm 1 from me

Deleted 1.

For more information about mail, type help mail.

Discussion Groups

There are a number of discussion groups on Valhalla. You are already a member of *Life, a group for general discussion of life in Valhalla. If you want to see a list of mail on *Life, type @mail on *Life. To read message 7 on *Life, type @read 7 on *Life. Discussion groups are just like mail, except that instead of the word ‘me’, you use the name of the discussion group. All of the mail verbs work with discussion groups.

To see a list of all of the discussion groups available to you, type @unsubscribed. To take part in a discussion, you need to subscribe by typing

@subscribe discussion-group

If you want to stop taking part in a discussion group, use

@unsubscribe discussion-group

and use @subscribed to see a list of the groups you’re currently subscribed to.

Talking With Text

Using pure text can be somewhat limiting. You can’t squiggle pictures in the margins, you can’t wave your arms or smile and expect the person at the other computer to see it. In Valhalla, you can wave your arms and smile using the emote verb already described:

:smiles disdainfully. "Funny as a crutch, Thor."

Balder smiles disdainfully. "Funny as a crutch, Thor."

You can add emphasis to a word or phrase by surrounding it with an asterisk. If you surround each word separately with asterisks, it’s a more staccato an emphasis.

Balder says, "*Where* did you put it?!"

Balder says, "*Where did you put it?!*"

Balder says, "*Where* *did* *you* *put* *it?!*"

You can yell (but you shouldn't very often) by using all capitals. (And if you accidentally hit your shift lock key, everyone will think you are yelling.)

Balder says, "Where did you put it?!"

If you want to set off a title without as much emphasis, use the underscore. It’s similar to italics, and is probably derived from the editor’s mark for italics1.

Balder says, "Have you seen _Gone With the Wind_?

And, of course, you can combine them as much as you want…

Balder looks at his tape collection quizzically. "Have you seen _Gone With the Wind_? *Bitchin'* movie.*WHERE* did you *put* it?!"

…but don’t overdo it, you’ll burn your keyboard out.

You can also use emoticons, although they should be limited to electronic mail. The most common emoticons are the smiley and the frown. They look sort of like a smiling and a frowning person… if you turn your head to the side… and use some imagination.

:*) :*( :^) :^( =*( =*)

Other emoticons exist. There’s an exhibit in the museum in Balmooa Park.

Interacting With Objects

Picking Them Up and Dropping Them

The basic commands that apply to objects are look, take, drop, and give.

look staff

take staff

drop staff

give staff to Thor

In Valhalla, these commands are called ‘verbs’. In order to ‘do’ something to or with an object, either that object or one of it’s ancestors must have that ‘command’ as a ‘verb’. Only programmers can create and program verbs.

For more information about using objects, type:

help manipulation

Looking At Them and Examining Them

You can look object to see an object’s description. Usually, looking at an object will tell you everything that the object’s creator wants you to know. If you want to see a list of the verbs on the object, and some of the properties, type @examine object. ‘Verbs’ are things you can do to or with the object. Drop and look are both verbs. ‘Properties’ are information about the object. Names, aliases, and descriptions are all properties.

I’ll talk a little more about this under Building and Advanced Building.

Getting Help

Valhalla has a built in help system. Type help to see it. Some parts of help that you may find helpful are:

help movement

help communication

help players

help manipulation

What is Valhalla?


Valhalla’s purpose is to provide a meeting ground in ‘virtual space’. It is a space on the Internet where people can interact in real time or by leaving messages. People in Valhalla can personalize their interactions by creating special rooms and objects. Valhalla is meant to provide a place for the University of San Diego community to meet with other communities on the Internet. Members of the USD community can sponsor on-line festivals, professional conferences, regular get-togethers, readings, and anything else that humans meet for, using Valhalla and the Internet.

Valhalla is open to anyone on the Internet. However, ‘programmer’ status will generally only be granted on the request of a member of the USD community, and then only if it will contribute to the general needs of Valhalla’s USD users.

Technical Stuff

From a technical standpoint, Valhalla is what is known as a MOO. MOO is a ‘programming language’ for creating multi-user dungeons (MUD). There are many other MUDs around. MOO is object oriented (thus, MUD, Object Oriented, or MOO). Don’t worry about what that means. MOO was created and is currently maintained by Pavel Curtis and Xerox PARC, who are to be commended for their work. They provide the MOO environment free of charge.

Valhalla is a MOO on one of the IBM compatibles at the University of San Diego, using the Linux operating system. Linux is a Unix look-alike. There are different versions of Linux available, but all are provided free of charge by the people who write and maintain them.

Finally, Valhalla is maintained by Thor and Balder, who can occasionally be seen wandering about the Circus Bazarre and the rest of Valhalla’s universe.

Where to Go for Help

There are many more MOOs out there, and many people using them. They’ve developed quite a support group.

The Newbie Arch-Wizard FAQ

On the Net, an ‘FAQ’ is a collection of Frequently Asked Questions—and their answers. The Newbie Arch-Wizard FAQ is for people setting up a MOO who don't know anything about MOOs. It's on a gopher site. Get to it via gopher at, and look in the directories technical and then MUD-MOO. The file is new-archwiz-faq.txt. If you're using World-Wide Web, the url is:

The Moo-Cows Mailing List

MOO-COWs is a group of people who use electronic mail to discuss MOO-related issues. In order to take part in the mailing list, you need to subscribe. Get more information about MOO-Cows at:

The Original MOO

Pavel Curtis’ MOO, LambdaMOO, is running at, on port 8888. There is also an ftp site designated for MOO issues, at, in /pub/MOO. The url for World-Wide Web is:

The official programmer's manual is there in text and postscript formats.

The Wide World of MOO

There is a special World-Wide Web server set up for MOOs at:

The Cerebus MOO Object Archive

There is a web site at for MOO objects. The World-Wide Web URL is:

If you create interesting objects that you want to share with the rest of the MOO world, write me via that web page.

Come to Valhalla

The full on-line Come to Valhalla includes the basic information you have here, plus more advanced information about building things, programming, and MOO management. Look for it at


We’ve already discussed a little bit about mail inside of Valhalla. Mail is a very important feature—it allows you to carry on discussions with other players even if you can’t get inside of Valhalla at the same time. It also allows you to take part in group discussions with a wide variety of Valhalla’s denizens.

Getting Around in Mail

What’s Available?

When you come into Valhalla, you’ll be told which discussion groups have mail on them that you haven’t read. If you want to double check later, on, you can type


to see a list of all of your discussion groups that have unread mail on them.

Reading a Lot of Mail

After you read the first piece of mail, you can simply type

@next on me


@next on discussion-group

to see the next message.

Deleting Old Mail

You can delete mail that you no longer need by typing

@rmm number on me

Your message numbers will continue to climb, however. You can reset the message numbers back to one with


Setting Your Mail Options

There are a number of things that the mail agent assumes about you, and you can change these assumptions. Type help @mail-option for more information.


Normally, mail assumes that you’re talking about yourself. If you type @next, it’ll assume you mean @next on me. If you set mail to be sticky, it’ll assume you meant whatever ‘mail box’ you used last time. If the last thing you typed was @next on *Life, another @next will also deal with *Life. Use

@mail-option +sticky

to make your mail verbs sticky, and

@mail-option -sticky

to ‘unstick’ your mail verbs.

Forwarding Mail to an Internet Address

Many people like to get all of their mail in one place. You can have your Valhalla mail forwarded to another Internet address (including if you have an address there) by setting your netmail mail-option:

@mail-option +netmail

Building Discussion Groups

You can build your own discussion group. The ‘parent’ discussion group is $mail_recipient. Here’s a basic, general access discussion group:

@create $mail-recipient named discussion-group-name

Your discussion group name cannot have any spaces in it.

@set discussion-group-name.readers to 1

By setting this property to 1, you’re giving everybody in Valhalla access to the group.

@describe discussion-group-name as "Description of discussion group

@move discussion-group-name to $mail_agent

Until you move the discussion group into the mail agent, it doesn’t matter that anyone else can take part in it, because they can’t see it, and won’t know it exists. Once it’s inside the mail agent, anyone can @subscribe to your discussion group. Your group will show up when anyone else in Valhalla lists discussion groups with the @unsubscribed verb.

Moderated Groups

A moderated group is one that can be read but not sent to. You might, for example, create a newspaper as a discussion group. Journalists would send their articles to you (the editor), and you would edit them and send them to the group, at which time all the readers will see it. To make a group moderated, set the ??? property to the names of the people who will be allowed to send to the group. Only these people can send.

@set #discussion-id to {#player_1-id,#player_2-id,…,#player_n-id}

You need to use the object identifier numbers because Valhalla can’t ‘see’ either the discussion group or the players.

Private Groups

You can make a group private by telling it exactly which people are allowed to read it. Instead of setting .readers to 1, set it to a list of the players who will be allowed to read it:

@set #discussion-id to {#player_1-id,#player_2-id,…,#player_n-id}

The discussion group will not allow anyone who is not on the list to join the discussion.


In Valhalla, you can build, or create objects for your player to carry around. You can also build rooms, buildings, or surfboards. There’s a special discussion group on Valhalla for talking about building things, called *Everything.

Building Things

Here’s an example:

@create $thing named Staff

You now have Staff with object number #80 and parent generic thing (#5).

look staff

You see nothing special.

@describe staff as "Balder's staff is a gnarly branch of an oak, tied at both ends by hemp yarn and inscribed with strange runes."

Description set.

look staff

Balder's staff is a gnarly branch of an oak, tied at both ends by hemp yarn and inscribed with strange runes.

look me

Balder the Brave strides across Valhalla with a strong purpose and a light in his eyes.

He is awake and looks alert.



Creating Objects

What did I do there? First, I created the object and named it. Then, I described it and fooled around with it.

@create $thing named Staff

Things with the dollar sign in front of them are ‘generic objects’. The object called $thing is the most basic thing you can have. In Valhalla, every object has parents. In this case, I created a child of $thing named staff. When I created the staff, Valhalla told me that it has object number #80. Sometimes, when Valhalla can’t tell what object you’re talking about (if there are two objects with the same name, or the object isn’t visible), you’ll need to use the object number instead. Look staff and look #80 are both the same thing, but I can look #80 even when the staff isn’t in the same room as I am.

@parent staff

Staff(#80) generic thing(#5) Root Class(#1)

I can see the ancestors of an object with the @parent command. The staff is a child of generic thing, which is a child of the Root Class.

@parent me

Balder(#78) generic wizard(#58) generic programmer(#59) generic builder(#4) generic player(#6) Root Class(#1)

An object’s parents determine what the object can do. My staff can do anything that a generic thing can do (which is, not much). I (Balder) can do anything that a generic wizard can do; anything that a generic programmer can do; anything that a generic builder can do; and anything that a generic player can do.

@parent here

The Fields of Valhalla(#11) generic room(#3) Root Class(#1)

When you say “here”, Valhalla assumes you mean “the place you currently are”. The Fields of Valhalla are a generic room.

You can build objects based on other objects you have created. I could build a second staff based on the first (although I see no point to it). I could also create a type of room called ‘field’ and base the Fields of Valhalla on ‘field’ instead of on ‘room’. Here are the standard generics that Valhalla has:

$thing Most things you’ll create will be $things.

$container Containers are objects that can hold other objects.

$note You can create notes with this. Try help $note.

$player People are all based on the generic player. Check your heritage!

$room Places where people can travel should be based on $room.

$exit Valhalla creates these when you do an @dig.

Look in Balder’s Basement in Asgard for more generics that you can use.

Describing Objects

After I @created the staff, I @described it. Until you describe an object, no one else can see what it is by looking at it. Until you describe it, they will see

You see nothing special.

The description of an object is a property of that object. We’ll talk more about properties later on. For now, whatever you

@describe object as…

is what other people see when they look at it.

Making Rooms

Rooms are just another type of object. The basic (generic) room is $room.

@create $room named "Balder's Hall","Hall"

You now have Balder's Hall (aka Hall) with object number #81 and parent generic room (#3).

@move me to hall

Balder's Hall is inside of Balder!

drop hall


@move me to hall

Balder's Hall

You see nothing special.


First, I created the room.

@create $room named "Balder's Hall","Hall"

I gave it two names. The first name is the object’s real name. The second name is an ‘alias’. An object can have many aliases. Aliases are simply other ways of refering to an object. It’s easier for people to type hall than to type Balder’s Hall.

I tried to go into the room, but Valhalla wouldn’t let me. When you create an object, you are automatically carrying that object. That means that the Hall was inside of me. Valhalla does not allow objects to be inside of the objects that are inside of them. First, I had to drop the Hall so that it was no longer ‘inside’ of me.

There’s nothing special about the Hall yet. I need to describe it.

@describe here as "The ceiling is made of huge vaulting oak beams. The walls are the hide of some great scaled lizard, and its scales glisten in the light of the flickering fire in the stone fireplace at the hall's north end.

Description set.


Balder's Hall

The ceiling is made of huge vaulting oak beams. The walls are the hide of some great scaled lizard, and its scales glisten in the light of the flickering fire in the stone fireplace at the hall's north end.

Let’s make another room, and make an entrance between the Hall and the new room.

@dig fireplace,fire|down,fire to Chimney

Chimney (#82) created.

Exit from Balder's Hall (#81) to Chimney (#82) via {"fireplace", "fire"} created with id #83.

Exit from Chimney (#82) to Balder's Hall (#81) via {"down", "fire"} created with id #84.

go fireplace


You see nothing special.

go down

Balder's Hall

The ceiling is made of huge vaulting oak beams. The walls are the hide of some great scaled lizard, and its scales glisten in the light of the flickering fire in the stone fireplace at the hall's north end.

The dig command is a bit complicated. Let’s break it down:

@dig fireplace,fire|down,fire to Chimney

The syntax is:

@dig entrances|exits to room

So, in the example, @dig created a room called Chimney. It created an entrance from here (Balder’s Hall) to the Chimney, called fireplace, with alias fire. It created an exit from Chimney to here called down, with alias fire. Anyone inside Balder’s Hall can use the fireplace or fire to move between the Hall and the Chimney. From the Chimney, they can use down or fire to move to the Hall.

They all need descriptions. Since I’m currently in Balder’s Hall, the only object I can see is the fireplace entrance. I need to refer to the chimney and the down exit with their object numbers. Valhalla told me what the object numbers were when I dug them.

@describe #82 as "The stone chimney is smokey and warm, and a bit cramped for anyone of normal size. Dirty elfs skitter about as they see you coming.

Description set.

@describe fireplace as "A blazing fire from the fireplace heats the entire room. You occasionally see rodents' faces popping down from the chimney and then disappearing.

Description set.

@describe #84 as "The fire below spews smoke and ash up the chimney and past you. What in the world are you doing here?

Description set.

look fire

A blazing fire from the fireplace heats the entire room. You occasionally see rodents' faces popping down from the chimney and then disappearing.

go fireplace


The stone chimney is smokey and warm, and a bit cramped for anyone of normal size. Dirty elfs skitter about as they see you coming.

look down

The fire below spews smoke and ash up the chimney and past you. What in the world are you doing here?

Note that, because the ‘fireplace’ is a passageway, when I ‘go fireplace’ I end up in the Chimney. Likewise, when I ‘go down’ I end up in Balder’s Hall. You never actually spend any time inside of passageways.

Hooking Your Rooms To Valhalla

When you create a room, no one else can get to it. Even you can only get to it by using the @move verb. You can’t go Balder’s Hall because there’s no entrance to Balder’s Hall. You can only create passageways between two areas that you own. So, only a wizard can hook things up to Valhalla. When you have your rooms ready for other people to use, tell a wizard. You can see if there are any wizards currently available by typing @who. Otherwise, send mail to either Balder or Thor.

You can hook up passageways between two rooms you do own, so you can create a mansion of a hundred rooms and carry it in your pocket if you want.

Advanced Building

Help building and help gen-index will give you a list of topics that might interest you. The command @classes generics will give you a list of all the built-in generic objects available for parenting.

Quotas and Audits

To see a list of the objects that you have, along with their id number and current location, type @audit me.

You can only create a certain number of objects. This is your quota. Once you create this many objects, you cannot create any more without getting rid of some of the ones you have. To get rid of an object, type @recycle object. If you can’t see the object, you’ll have to use its object number. Once you recycle an object, it is gone. You cannot get it back. Don’t recycle an object that’s important to you.

If you ask a wizard nicely, you can get your quota increased.

Talking to the MOO

Sentence Structure

It helps to know how Valhalla interprets what you type. The simplest way to do something is to type a single verb, such as home. ‘Home’ is a verb that only works on yourself, so it doesn’t need to know any more. A verb is the word you use to tell Valhalla that you want to do something.

You can also have direct objects, indirect objects, and prepositions. For example, in

give chocolate to Garm

the chocolate is the direct object, and Garm is the indirect object of the verb give. Valhalla first attempts to find a verb. ‘Give’ is the verb in this case, and the verb is always the first single word typed. Then, it looks for a preposition (in this case, ‘to’), and assumes that what is on the left (chocolate) is the direct object, and what is on the right (Garm) is the indirect object. If one of your objects contains a preposition, you can confuse Valhalla. To keep Valhalla from looking at the prepositions inside your object, enclose the object text in quotation marks. For example:

show "Like Water For Chocolate" to Garm

If you keep in mind how Valhalla works, you’ll be better able to phrase things when you try to do something.

If there is no preposition, everything after the verb is the direct object.

Where Does Valhalla Look for Verbs?

Verbs can only be found on objects. You are an object, and you have quite a few verbs on you. So, most likely, does the room that you are in. When Valhalla looks for a verb, it looks on the player who typed the verb first. If it doesn't find a matching verb there, it looks in the room that the player is in. If it still doesn't find a matching verb, it looks on the direct object of the sentence, if there is one, and finally on the indirect object of the sentence, if there is one.

If it hasn't found any verb at all, you will be told something to the effect of “Valhalla doesn't have any idea what you're trying to do.” Sometimes, however, Valhalla will find the verb that you typed, but with a different sentence structure. If so, Valhalla will suggest a different way of typing your sentence to get the desired results.


Home, Sweet Home

Every player (and most objects) have a home. For players, your home is where you go when you sleep. When you @quit Valhalla, your player is whisked away to home. You can also teleport home by typing home.

By default, your ‘home’ is The Fields of Valhalla. If you create your own room, or find another place you’d rather call home, go there and type:


Balder's Hall is your new home.

From now on, this is your home.


You click your heels three times.

Balder's Hall

The ceiling is made of huge vaulting oak beams. The walls are the hide of some great scaled lizard, and its scales glisten in the light of the flickering fire in the stone fireplace at the hall's north end.

Clicking your heels three times may not be appropriate for a great warrior of Valhalla. You can change this. It’s what is called a message. Type

@home me is "You smash your boots to the ground and the earth opens up.

You set the "home" message of Balder (#78).

and your ‘home’ message is changed.


You can (and should regularly) change your password. Use:

@password old-password new-password

For example,

@password iqoqoj LoveSexy

New password set.

You should choose a password that is easy for you to remember, and hard for anyone else to guess. Your password keeps other people from using your player when you’re not looking.

Page Messages

Home is an example of a message. Your player has many messages that you can change. To see a list of the messages that you can change, type @messages me. Many people commonly change the page messages, page_absent, page_origin, and page_echo. Page_absent is the message other people get when they try to page you but you’re asleep. Page_origin is the message other people get when you page them, and page_echo is the message other people get when they page you.

The syntax for changing a message on yourself is

@message me is "New Message.

For example,

@page_absent me is "%N is sleeping in %l, dreaming of pillaging the European countryside.

You set the "page_absent" message of Balder (#78).

When someone else pages you and you’re not in, they’ll see:

page balder "Hey, Balder, what's up?

Balder is sleeping in Balder's Hall, dreaming of pillaging the European countryside.

The “%N” and “%l” are pronoun substitutes. I’ll talk more about those later. For the moment, use %N to refer to your name when it appears at the beginning of a sentence, and %n when it appears inside of a sentence. The same goes for %L, which is the location of the person who owns the message. Use %l (lowercase L) when it appears inside a sentence, and %L at the beginning of a sentence. Pronoun substitutes only work with certain verbs (of which page, obviously, is one).

Pronoun Substitution

‘Pronoun subs’ are ways to make your messages more personal. They are ‘place-holders’ for the name of the person using an object, the location of the object, or whatever personal or possessive pronoun the person using the object needs. For a full description of how to use pronouns, type @help pronouns.

Pronouns come in two flavors: capitalized and uncapitalized. Use capitalized pronouns at the beginning of sentences, and uncapitalized ones inside of sentences. You’ve already seen “%L” and “%l” for location. It’s the location of the object that the message is on. All pronouns are preceded by a “%” sign. If you really want a “%” sign, use “%%”.

Let’s say we’ve got a drinking fountain, and once in a while it sprays the drinker embarrassingly. We could use the message:

@oembarrass fountain is "%N sprays water all over %r, and a puddle forms around %o and the %t on the floor of %l.

@embarrass fountain is "The %t sprays water all over you. %L grows quiet as everyone turns to look at you.

This is overdoing it a just a bit. Let's say the drinking fountain is in “the Fields of Valhalla”, and Balder takes a drink, triggering the embarrassing message. Balder sees:

The drinking fountain sprays water all over you. The Fields of Valhalla grows quiet as everyone turns to look at you.

Everyone else sees:

Balder sprays water all over himself, and a puddle forms around him and the drinking fountain on the floor of the Fields of Valhalla.

Here are the commonly used pronoun substitutions. Each one also has a capitalized version.

%n the player

%t this object (i.e., the object that holds the message,… usually)

%d the direct object from the verb line

%i the indirect object from the verb line

%l the location of the object

%s subject pronoun, either `he', `she', or `it'

%o object pronoun, either `him', `her', or `it'

%p posessive pronoun (adj), either `his', `her', or `its'

%q posessive pronoun (noun), either `his', `hers', or `its'

%r reflexive pronoun, either `himself', `herself', or `itself'


Objects can require keys in order to ‘use’ them. The player who attempts to use the object must either be or have the key.

Object Class Key required for:

$thing taking

$note/$letter taking or reading

$container taking or opening

$exit leaving

$room entering

If you @lock an object with yourself as the key, then you are the only person who can use that object. If you want to specify more complex keys, you have to understand the ‘language’ of keys, which is a bit weird. It’s sort of like saying “let Bob or Jo or Bill but not anyone carrying my donut use this object”. But you have to say it in computer talk:

@lock here with (Bob || Jo || Bill) && !donut

It’s like that logic stuff you got from algebra. Use ‘||’ to say ‘or’, ‘&&’ to say ‘and’, and ‘!’ to say ‘not’. And you can group parts together with parentheses. In the above example, if it’s Bob, Jo, or Bill trying to get in, the part between parentheses comes out true. And as long as none of them are carrying your donut, !donut comes out true as well (because donut comes out false, and not donut is the opposite). Which lets them in. If anyone besides Bob, Jo, or Bill tries to come in, that part turns out false, and the room doesn’t let them in. Likewise, if anyone is carrying your donut, that part comes out false and the room doesn't let them in, even if they are Bob, Bill, or Jo. At least, until they drop your donut.

The Truth Table, in case you’ve forgotten your high school algebra:

English Computerese Result
true and true true && true true
true and false true && false false
true or true true || true true
true or false true || false true
not true !true false
not false !false true

Here are some complex examples:

(Bob || (Jo && Balder's Key) || me) && !#13

Anyone who is carrying whatever object has number #13 is locked out., even me: suppose I’m carrying object #13 and Balder’s Key:

(false || (false && true) || true) && !true

(false || false || true) && false

true && false


Bob can come in as long as he’s not carrying #13, and Jo can only come in if she’s carrying my key. No one else can come in at all. Let’s say Fred, who is carrying my key but not object #13, tries to come in:

(false || (false && true) || false) && !false

(false || false || false) && true

false && true


More commonly, you’ll probably use simple things like only allow yourself into the room:

@lock here with me

or only allow your friends and yourself into the room:

@lock here with me && CapVideo && Thor && Jenni

or lock a particular obnoxious person out of your room:

@lock here with !Fred

You can also use keys to make it so that only certain people can read notes and letters. I’ll talk about that in a moment. Type help keys for more detailed information about keys.


To see a list of messages on an object, type @messages object-name. You can get a list of some of the verbs and properties on an object by using @examine object-name.

Drop and Take Messages

If you @lock a thing, people who don’t meet the criteria you specify cannot take the object. The message they’ll see when they try to take it is take_failed. The message that everyone else sees when they try to take it is otake_failed. When a message is exactly the same as another message, but begins with o, the first message is for the player, or the person using the verb, and the second message (with the o) is for everyone else in the same room.

@take_failed Platter of Stale Donuts is "You pick up the entire %t, but your guilty conscience forces you to put it back. How about just eating a single donut?

@otake_failed Platter of Stale Donuts is "%N tries to hoard the %t, but %p conscience gets the better of %o.

@take_succeeded "Sword in the Stone" is "You pull the sword from the stone. Everyone else is looking at you *awfully* funny.

@otake_succeeded "Sword in the Stone" is "With a majestic flourish, %n jerks the sword from the stone. A shaft of light from the sky illuminates %o with a divine glow.

You can also set the drop messages, which the player (drop_succeeded, drop_failed) and others (odrop_succeeded and odrop_failed) see when the player drops or throws an object.


A container is a thing that can hold other things.

@create $container named steamer trunk,steamer,trunk

put staff in trunk

You put the staff in the steamer trunk.

Containers normally have an opacity of 1, which means that you can see into them when they’re open, but not when they’re closed. You can use

@opaque container is 0

to make a clear container, and

@opaque container is 2

to make a container that is opaque even when it is open. Containers can be opened and closed. If you want to restrict who can open a container, you can use keys, with:

@lock_for_open container with key

Unlock a container with @unlock_for_open. Since containers are $things, @lock works the same for containers as for other things, restricting who can and cannot take the container.

Notes and Letters

A note is a thing you can write on. A letter is a note that can be given to someone and then burned (thus saving your quota).

You can encrypt a note or letter with a key, so that only you or people you specify can read the note:

encrypt Balder's Notepad with me || CapVideo

allows only me (Balder) or Captain Video to read Balder’s Notepad. See the part about keys, on page 22, for more information about ‘constructing’ encryption keys. To make it so that anyone can read the note, use:

decrypt object

This erases the keys you’ve constructed for the object. @Locking a note or letter is the same as @locking a thing.


To see a list of messages that you can change for your room, go into the room and type @messages here. For a list of messages on an exit, type @messages exit-name.

Arrival and Departure Messages

Entrances and exits are normally quiet. When a player goes through a door, the door simply plops the player out the other side. In some cases, you’ll want an entrance to say something, either to the player or to the other players in the room that the player is leaving or entering. Here are the messages for exits (which, on the other side, are entrances):

leave What the player sees when he leaves the room.

oleave What the other players see when the player leaves.

arrive What the player sees when he enters the room.

oarrive What the other players see when the player enters.

For example, I might want to set the leave and arrive messages on the fire (that leads to the chimney of Balder’s Hall) as:

@leave fire is "No fear of getting burned, eh, %n?

You set the "leave" message of fireplace (#83).

@arrive fire is "The flame burns your butt as you hang in %l.

You set the "arrive" message of fireplace (#83).

go fire

No fear of getting burned, eh, Balder?

Balder's Chimney

The stone chimney is smokey and warm, and a bit cramped for anyone of normal size. Dirty elfs skitter about as they see you coming.

The flame burns your butt as you hang in Balder's Chimney.

And, so that people in the room see what’s going on, I might:

@oleave fire is "takes leave of %p senses and crawls into the burning fire.

You set the "oleave" message of fireplace (#83).

@oarrive fire is "climbs up out of the fire, smoke rising from %p eyebrows.

You set the "oarrive" message of fireplace (#83).

Note that I did not use “%N”. The oleave and oarrive messages automatically put the player’s name in front of the message, whether you want it or not, so you’ll have to want it. When I go up the chimney, the people in Balder’s Hall see:

Balder takes leave of his senses and crawls into the burning fire.

If there’s already someone in the chimney, they see:

Balder climbs up out of the fire, smoke rising from his eyebrows.

Note the use of “%p” for possessive pronoun. This takes care of whether or not the player using the exit is a him, a her, or an it.

Who Location

When people are in your room, your room is listed whenever anyone does @who. How it appears depends on the rooms who_location message. Normally, it is simply “%T”, and that’s recommended. But you can change it:


Player name Connected Idle time Location

Balder (#78) 11 minutes 0 seconds Balder's Hall

Total: 1 player, who has been active recently.

@who_location here is "By the fire in %t.

You set the "who_location" message of Balder's Hall (#81).


Player name Connected Idle time Location

Balder (#78) 11 minutes 0 seconds By the fire in Balder's Hall.

Total: 1 player, who has been active recently.

Free Home and Residents

Normally, the rooms you create will allow anyone to make it their home.1 You can lock people out by setting the property free_home to 0. (In computer talk, ‘zero’ is often used for no or false. ‘One’ is used for yes or true.) If you have free_home set to 0, the @resident verb will allow specific players to use your room as their home.

@set here.free_home to 0

@resident Carol, Bob, Ted, Alice

Now, the players Carol, Bob, Ted, and Alice can set your current location as their home. You can only do set properties and residents for rooms that you own.

Locking Your Doors

You can restrict access to your room to certain people, or restrict specific people from your room. For example,

@lock here with me

will make it so that only you can get into your room.

@lock here with !capvideo && !thor

will lock both CapVideo and Thor out of your room.

@Lock here with me || (bible && cross)

will lock everyone out except you or someone carrying your bible and your cross. See page 22 for more information about making keys to lock your rooms up with. Use

@unlock here

to unlock a room so that anyone can get in. @Unlock erases your key requirements, so if you want to remember them, write them down.

Making Children

Messages (properties) get transferred through children. So, if you want a new object with similar messages to an object you already have, make the new object a child of the other object, either with

@create other object named new object

or by using

@chparent new object to other object

on an object you’ve already created. If you can’t currently see the other object or the new object, you’ll need to refer to them by object number. Only you can create children from objects that you’ve made, unless you make the object fertile:

@chmod object to +f

Fertile objects can be used in @creates by anyone.

Using Universal Resource Locators (URLs)

Objects in Valhalla can have ‘URLs’ attached to them. If someone looks at the object and has the correct client software (such as HyperMU* for the Macintosh), the URL will be displayed at their computer. A URL can be any standard Internet service that is covered under the World Wide Web.


So you want to become a MOO1 programmer? Run, do not walk, to the LambdaMOO ftp site and get the latest text version of the LambdaMOO Programmer’s Manual. You will need to continually reference this book. If you want to print it out, get the postscript version, but I also recommend keeping the text version on your personal computer so that you can refer to it and do searches on it. I’m only going to talk about the basics of MOO programming here. You'll need the official manual as a reference, and you should read through it at least once.

Inside the MOO, help programming and help prog-index will give you a list of topics that might interest you. The command @classes utilities will give you a list of all the built-in utility objects available for programming. There’s a special discussion group for programmers on Valhalla called *Universe.2

Becoming a Programmer

In order to become a programmer, you need to talk to a friendly wizard. Most likely, you will be given a new player to use as a programmer, and you will keep your current player so that you can use it as a guinea pig for your new creations.


You’re already quite familiar with properties. The messages you’ve been setting are properties, as is your name and your description. Most of the properties you’ve dealt with so far have been string properties. There are four basic kinds of properties in MOO.


not written


not written


not written


not written


Verbs are the ‘commands’ of the MOO. You’ve been using verbs left and right. When you ‘look’ or ‘go’, when you talk, emote, page, or whisper, you’re using verbs.

Classes of Objects

Verbs must be attached to objects, whether the object is a player, a room, or some thing. Verbs should be attached to appropriate objects. If you have a cat named Lucretia, and you want people to be able to kick it, you should attach the kick verb to Lucretia, and not the room you happen to be in. People are going to want to kick your cat no matter where they find it. A kick verb on a room might be appropriate if the room is a kick-boxing arena.

MOO is an object oriented programming language. This means that it has classes of objects. When you look at the parents of an object, you’re looking at the classes that the object belongs to.

@parents Lucretia

Lucretia(#392) generic cat(#259) generic animal (#258) generic thing(#5) Root Class(#1)

Lucretia is a member of the class generic cat. Cats, in general, are members of the class generic animal, which are members of the class generic thing. Everything in the MOO is based on the Root Class.

Suppose you type kick Lucretia. Assuming that there is no kick verb on you or on the room you are in1, the MOO looks to see if Lucretia has a kick verb. If she does, the MOO ‘runs’ that kick verb. If not, the MOO checks to see if cats can be kicked; then, it checks animals, and then things, and finally the Root Class.

This order of verb-searching means that higher-order objects can override verbs in lower-order objects. If both generic thing and generic cat have a kick verb, only the verb on generic cat is used by the MOO.

Sentence Structure

There are three basic sentence forms in MOOs:


verb direct-object

verb direct-object preposition indirect object

When you create a verb, you need to tell the MOO what kind of sentence the verb belongs in, and what kind of direct or indirect objects are allowed. For example,

@verb here:cough none none none

creates a cough verb in the current room. The cough verb only works if the player doesn't type anything except ‘cough’.

@verb staff:swing this at any

creates a swing verb on the staff. This verb needs the direct object to be the staff (this), the preposition to be at1, and the player must swing it at something, although this something can be anything.

The LambdaMOO Programmer’s Manual discusses verbs in much more detail. The important thing to remember here is that, when the MOO starts looking for a verb, it basically ignores any verbs whose sentence structure doesn't match what the player typed. If the player types cough loudly, the MOO will not use the cough verb we created above. If the player types swing staff in time, the MOO will not use the swing verb we created.

In both cases, if the MOO doesn't find an appropriate verb/sentence structure combination, it will make suggestions to the player. In the above examples, we might expect:

cough loudly

I don't understand that.

Try this instead: cough

swing staff in time

I don't understand that.

Try this instead: swing staff to time

Editing Properties and Verbs

Properties: Notedit

You can edit string properties, or lists properties that are lists of strings, with the @notedit verb: @notedit For example, if you want to give the current room a description that has more than one line—i.e, that is a ‘list’ of strings—use @notedit:

@notedit here.description

The property editor works just like the mail editor, except that you use save when you’re finished, instead of send. Save saves the changes you’ve made to the property. When you’re done editing and want to exit the editor, use done. The done verb doesn’t save the changes you’ve made—that’s what save is for—but it does keep track of what you’ve done if you haven’t saved. You can return to your editing by typing @notedit without anything else.

Verbs: Edit

When you need to edit a verb, you use @edit object:verb. It’s the standard editor that you’ve used to send mail and possibly to edit properties. When you’re ready to save the changes you’ve made, type compile. You will be told if there are any ‘syntax’ problems in the verb, and what line these problems are in. Use done to leave the editor.

The Generic Swinging Weapon

Even though I’m going to leave the majority of programming instruction to the official manual, I’m a firm believer that you can never have too many examples. This is Valhalla. Lots of gods with short tempers. We will have swords, staves, and hammers coming out of (and into) our ears. Let's make a generic swinging weapon to base them all on.

@create $thing named generic swinging weapon,swinger

@describe swinger as "a nondescript weapon of untold power; be careful with it: you might knock someone's eye out!

We need a verb of some sort so that we can hit people with it. What are the possibilities?

hit Jack with sword

strike Thor with staff

There is a big problem with both of these. Remember the order of searching? The MOO is going to look at Jack and Thor (the direct objects) before it looks at sword or staff. If I bother them too much, they’ll create a swing verb on themselves:

@verb me:"Hit Strike" any with this

@edit me:Hit

"player:tell("You miss.");

"player.location:announce($string_utils:pronoun_subs("%N strikes at %d with %p %i. %D dodges nimbly, and %n strikes the ground, leaving %r embarrassed and revealing %p utter incompetence."));



Since the MOO will get to this verb before it gets to ours, whenever we try to hit or strike Thor, we'll see:

You miss.

And everyone else will see:

Balder strikes at Thor with his staff. Thor dodges nimbly, and Balder strikes the ground, leaving himself embarrassed and revealing his utter incompetence.

Do we really want that? How about, since this is a generic swinging weapon:

swing staff at Thor


@verb swinger:swing this at any

@edit swinger:swing

The @verb creates the verb ‘swing’ on ‘swinger’. And then @edit allows us to edit it, and add instructions:

"if (valid(iobj))

If the player typed a valid object—something that exists—do the rest of this. Otherwise, Valhalla will jump down to the ‘else’ a couple lines down.

"player:tell("You hit ",," with your ",,".");

"player.location:announce_all_but({player,iobj}, $string_utils:pronoun_sub("%N hits %i with %p %d. It is a crushing blow."));

Here, we first tell the player who swung the weapon that the weapon (‘’) hit the target (‘’). ‘Name’ in each case is a property of the object referred to by ‘this’ and ‘iobj’. You refer to object properties with Tell is a verb that exists on player. We use it by typing player:tell. Announce_all_but is a verb that exists on the room that the player is in. We know the room because it is in the player’s property location. So, player.location:announce_all_but uses that verb. First, Valhalla interprets ‘player.location’, and then looks for the verb announce_all_but on that location. This is how we refer to verbs: object:verb(information for the verb).

Then, we tell everybody in the room—except the player, who we already told, and the target (‘iobj’), who we’ll tell in a moment—the same thing. Notice that we also call the pronoun_sub verb to interpret all those ‘%’ things. The pronoun_sub verb is on an object called $string_utils.

"if ($object_utils:has_callable_verb(iobj,"tell"))

"iobj:tell($string_utils:pronoun_sub("%N swings %p %d at you and deals an ugly wound. Good lord, %i, are you going to stand for that?"));


Here’s a complete if statement. If the target (‘iobj’) has a verb that we can use called ‘tell’, Valhalla will use the verb after the if statement and before the endif statement. In this case, it tells the iobj that it has been hit by the player swinging the weapon.


"player:tell("I don't see any ",iobjstr," here. Feeling a little troubled?");

"player.location:announce($string_utils:pronoun_sub("%N appears to be developing an interesting rapport with %p %d"));


This else and endif belong to the first ‘if’ at the beginning of this verb. The part between the else and the endif here will only be used if the if (valid(iobj)) comes back and says “no, the player didn’t refer to a valid object.” In other words, the MOO uses the first part (between the if and the else) if the statement valid(iobj) is ‘true’; else it uses the second part (between the else and the endif).

And what we’ve decided to do is, first, tell the player that we couldn’t find any ‘iobjstr’ to swing at, and, second, announce to everyone in the room that the player is doing something strange. Iobjstr is the text after the first preposition. It’s like iobj, except that it’s text instead of an object number. Announce is a verb that all rooms have, and it tells everyone in the room—except for the player who called the verb—whatever we put between the parentheses. In this case, that the player “appears to be developing an interesting rapport with” a generic weapon.


Compile tells the MOO to check the verb for errors, and then save the verb so that it can be used. You must compile your verbs before what you typed can be used.


Done returns you to wherever you were before you started editing the verb.

@chparent staff to swinger

Balder already created a staff in order to demonstrate creating objects. The @chparent command makes that staff a child of swinger, as if Balder had originally created it with @create swinger named staff. The staff now can do anything that a generic weapon can.

swing staff at Captain Video

You swing the staff at Captain Video

Everyone else (except Captain Video) sees:

Balder hits Captain Video with his staff. It is a crushing blow.

And Captain Video sees:

Balder swings his staff at you and deals an ugly wound. Good lord, Captain Video, are you going to stand for that?

Now, this isn’t really that interesting of a generic. You can @create all the staves, swords, and maces you want, they’ll still all “hit” and “deal ugly wounds”. At the end of this section, I’ll show you a better form of generic, that includes messages—properties that the owner can change, like all of the messages we fooled around with in Advanced Building.

The Advantages of Being Object-Oriented

Let’s make a present for Thor. First, we need to complete one more thing on the generic swinging weapon. We need to make it fertile.

@chmod swinger to +f

This adds ‘fertility’ to the swinger. Until an object is fertile, only the owner can make children from it. Anyone can make children from a fertile object. Now that swinger is fertile, anyone in Valhalla can @create swingers named whatever they want.

@create swinger named "Thor's Hammer",hammer,Mjolnir

Now, as anyone who reads comics—I mean, studied Norse mythology—knows, Thor’s Hammer is not your average weapon. One of its biggest properties is that it returns to Thor after Thor throws it.

Right now, Thor’s hammer can be ‘thrown’ just like any other object. It’s a $thing, and all $things have a throw verb which allows them to be thrown. Because Valhalla is object-oriented, we can override the basic throw verb with our own:

@show hammer:throw

Object #98 does not define that verb, but its ancestor #5 does.

#5:"dr*op th*row"

Owner: Thor (#2)

Permissions: rxd

Direct Object: this

Preposition: none

Indirect Object: none

I use the @show command to find out what the exact syntax for throw is. If I don’t copy it exactly, my ‘throw’ may not override all instances that players will use.

@verb hammer:th*row" this none none

@edit hammer:throw

"if (player != this.owner)



"player:tell("You fling the ",dobjstr," across the sky.");

"player.location:announce(," flings ",player.pp," ",dobjstr," out of sight!");

"player.location:announce("The ",dobjstr," flips back around and returns to ",,".");

"player:tell("Your ",dobjstr," returns to your grasp.");




The important thing to look at here is the pass(@args); verb. This passes the sentence to the parent verb. If anyone other than the hammer’s owner throws the hammer, it throws normally. If the owner (Thor) throws it, we take control and send out our special messages. By passing control on to the parent verb when we do want the hammer to be thrown normally, we don’t have to worry about what goes on in throwing an object, and, if the administrators ever improve their ‘throw’ verb, our own ‘throw’ verb will reflect these improvements.

Also, the original ‘throw’ verb is combined with drop. We didn’t override drop at all, so if Thor drops his hammer, it won’t return to him.

If you have any other questions about the statements in this verb, see the LambdaMOO Programmer's Manual, available at all fine virtual bookstores.

A Better Generic Swinging Weapon

@create $thing named generic swinging weapon:generic swinging weapon,swinger

@describe swinger as "a nondescript weapon of untold power; be careful with it: you might knock someone's eye out!"

@prop swinger."swing_msg" "You &hit %i with your %d, &wounds."

@prop swinger.tswing_msg "%N &ohits you with %p %d, &wounds. &tcomment"

@prop swinger.oswing_msg "%N &ohits %i with %p %d, &wounds."

@prop swinger.wounds_msg "dealing a deadly wound"

@prop swinger.no_target_msg "I don't see any %i here. Feeling a little troubled?"

@prop swinger.ono_target_msg "%N appears to be developing an interesting rapport with %p %d."

@prop swinger.hit_msg "hit"

@prop swinger.ohits_msg "hits"

@prop swinger.tcomment_msg "Good Lord, %i, are you going to stand for this?"

@prop swinger.help_msg ""

@notedit swinger.help_msg

"The generic swinging weapon has the following messages:

" tswing: What the target sees when the weapon is swung.

" swing: What the swinger sees when the weapon is swung.

" oswing: What others see when the weapon is swung.

" no_target: What the swinger sees when the weapon is swung at a target that doesn't exist.

" ono_target: What others see when the weapon is swung at a target that doesn't exist.


"In addition, the following 'ampersand' substitutions can be placed in the above messages:

" &wounds: Should be set to the kind of wounds the weapon does as a phrase: "dealing a deadly wound"

" &hit: What the weapon does when it hits as the swinger sees it: "hit"

" &ohit: What the weapon does when it hits as others see it: "hits"

" &tcomment: An extra comment for the target. Should be a complete sentence. "Good Lord, %i, are you going to stand for this?"


"For the current state of the above messages, use the @messages verb.


"Remember to be careful what you do with this thing! We don't want any ownerless eyeballs floating around Valhalla.

@verb swinger:swing this at any

@program swinger:swing

if (valid(iobj))


player.location:announce_all_but({player, iobj}, $string_utils:pronoun_sub(this:hitting_sub(this.oswing_msg)));

if ($object_utils:has_callable_verb(iobj, "tell"))








@verb swinger:hitting_sub this none this

@program swinger:hitting_sub

The_Message = args[1];

Substitute_List = {{"&hit", this.hit_msg}, {"&ohits", this.ohits_msg}, {"&wounds", this.wounds_msg}, {"&tcomment", this.tcomment_msg}};

Munged_Message = $string_utils:substitute(The_Message, Substitute_List);

return Munged_Message;

Forks and Tasks

Let's go back to Thor's hammer. We're not really letting him throw his hammer. We just tell everybody he threw it, which is almost the same thing. But we can also have the hammer actually be thrown, and then return after a short bit of time. We’ll re-write throw so that when Thor throws his hammer, it waits a bit at the destination, and then sails through the air back into his hand.

MOOs do not allow long-playing verbs. Any verb that takes too much time is terminated abruptly, with nary a polite goodbye. If your verb needs to wait before doing something, you have to tell it to go to sleep.

Using Files

The File Utilities Object

not written


Creating Players

To create a player, you need to specify the player’s name (which must be one word), the player’s e-mail address, and an optional comment:

@make-player name e-mail@address comment

For example, to create a player for Captain Video, with name Captain, whose electronic mail address is, use:

@make-player Captain Captain Video

You will be told what the player’s password and object number is. Write them down. You’ll need to give the password to the person so that they can log in with their player, and you may need the number to refer to the player when you can’t see them.

Creating Wizards, Programmers, and Builders

Players can’t do a whole lot except interact. Most people will probably want to be, at least, builders1. This means that they can build objects, although these objects must be based on other objects that a programmer has made. A programmer is a builder, and a wizard is automatically a programmer and a builder. Most people should not be wizards. Wizards have the ability to kill other players, to muck with other players’ objects, and to cause considerable havoc if they aren’t responsible and competent.

You also do not want to create wizards out of long-existing player. When you turn a player into a wizard, all of the verbs that player created have all the rights of wizards. Including the ones they wrote before they knew how to program. If you want to give wizard status to a long-existing player, make a new player, turn it into a wizard, and give it to the person. This also ensures that the person has a ‘non-wizarded’ player to use when testing new verbs.

You should generally leave the task of designating who is and is not a wizard to the administrator. It is their responsibility to delegate authority to the lesser wizards of the MOO.

Create builders, programmers, or wizards with the following commands:

@chparent #playernumber to $builder

@programmer #playernumber

@chparent #playernumber to $wiz

In addition, for wizards, the wizard property must be set. Wizards must be programmers before they can be wizards:

@set #playernumber.wizard to 1

A wizard can take away all programmer and builder status with the last command, which turns the player into a non-builder.

@chparent #playernumber to $player

@set #playernumber.wizard to 0

@set #playernumber.programmer to 0

Only the grand-high wizard, Thor, can take away wizard status.1



When you get the latest version of MOO, it’s in source code format. You need to compile the source code so that it will run on your computer. If you are using a Unix computer, it should be easy: type make and press return. If it runs into some errors, you’ll have to talk to a programmer about fixing them.

Choosing Wizards

You’re not going to be able to do everything yourself. You may not even personally know much about programming. That’s what you’ll need wizards for. Wizards are MOO players to whom you delegate authority. Wizards can modify any part of the MOO, and can edit and create verbs that affect everyone. Obviously, you should only choose wizards who you can trust, and who you know are reasonably competent.

Choosing Administrators

On Valhalla, there’s a property called #0.admins that lists which players are administrators. You can edit this list with @notedit. When your administrators write verbs that only administrators should be able to use, they need to have their verbs check against this list.

Login Stuff

You will almost certainly want to personalize what potential members of your MOO see when they first connect. The $login object contains everything that can be seen or done while in the ‘waiting area’ before logging in to your MOO.

Welcoming Message

Your welcome message explains what the purpose of your MOO or the thme of your MOO, or both. You can also add a little help into the welcome message, for new members who may not remember exactly how to get inside. The welcome message property is $login.welcome_message. You or one of your wizards can use @notedit $login.welcome_message to edit and change the message text.

Player Creation

When players are created by you or one of your wizards, and an electronic mail address is specified for the player, Valhalla sends the player a message over electronic mail, telling them that the player is ready, and how to get to it. The subject of the message is in $wiz_utils.new_player_subject, and the text of the message is in $wiz_utils.new_player_message. You can @notedit these properties if you need to modify them.1 Type help $wiz_utils:new_player_message for more information.

This mail message is only sent if an external electronic mail address (outside of the MOO) is given, and (because no e-mail address is specified) is not sent to people who create their own players at the Valhalla’s entrance.

Maximum Users

not written

Monitoring Players


not written


Dump Interval

not written



not written


not written

Discussion Groups

The MOO has it’s own set of discussion groups. They operate through the MOO’s mail functions. You can create and maintain groups for any topic you desire. The basic discussion groups in Valhalla are Life, the Universe, and Everything.

Creating A New Discussion Group

You’ll want to read the help, by typing help $mail_recipient. You need to create a child of $mail_recipient, describe the child, set the readers property to 1 (so that anyone can read it), and then move the child to $mail_agent:

@create $mail_recipient named Life-in-Asgard

@describe Life-in-Asgard as "A discussion group specifically for discussing the trials and tribulations of living in the city of Asgard.

@set Life-in-Asgard.readers to 1

@move Life-in-Asgard to $mail_agent

If you want to make the discussion group available only to a certain group of players, follow the help for $mail_recipient.

New Generics

On Valhalla, there are five Valhalla classes that ‘intercept’ the standard generic classes. These are:

ValhallaRoomClass Intercepts $room

ValhallaThingClass Intercepts $thing

ValhallaExitClass Intercepts $exit

ValhallaPlayerClass Intercepts $player

ValhallaRootClass Intercepts the root class.

If you want to make changes to an entire class of objects (such as all players, for example), you can ask one of your wizards to change the corresponding Valhalla class.

Each time you upgrade to a newer version of MOO, the standard generics are replaced with newer versions. By making your changes to a separate class that has been inserted into the class hierarchy, it will be easier for you to make upgrades.

New Help

not written


If you want Internet access in your MOO, it has to be enabled twice: first, whoever compiles the MOO code on your machine has to enable it, and second, you need to set $network.enabled to 1.


not written


The current standard for gopher access in MOOs is the Generic Gopher Slate. The MOO code for it is available at the LambdaMOO ftp site, in /pub/MOO/contrib. Gopher is, of course, pretty much dead. Support for this may be disappearing from Valhalla.

World-Wide Web

not written

Usenet News

not written



not written


not written


not written

Open source license

Gnu Free Documentation License

Version 1.3, 3 November 2008

Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. <>

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.


The purpose of this License is to make a manual, textbook, or other functional and useful document “free” in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

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