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# An Introduction to IF

Interactive Fiction is a fancy name for 'text adventures', thought up by a company called called 'Infocom' circa 1979. Text adventures themselves probably started with 'Colossal cave' by William Crowther. Modern IF is still largely a text medium: you type your order to the game, and it responds. However, the format of IF has changed since the 1980s - modern innovations include games without puzzles (Photopia, The Cove), where the aim is much more to explore the world the author created than to 'win' a game. Of course, more traditional works still exist and are being created.

While games can vary widely, even the ones that Zoom can run, they usually have a few things in common. Commands are usually entered at a '>' prompt. Many verbs and commands are common through all games. The parser, the part of the game that tries to understand your input, can usually understand fairly complicated commands and can help you with complex aspects of the virtual world.

## Common verbs

Probably the three most used verbs in a game are `LOOK`, `INVENTORY` and `EXAMINE`. You can `LOOK` to get a description of the location you are currently in, take an `INVENTORY` to see what you are carrying, and `EXAMINE` things to discover more details. Often a game will mention important objects in the room description as well as separately: examine everything you can to find these. Movement in IF is usually through the 8 compass directions, so you can, for instance, `GO NORTH` to try to leave a location to the north. Some games use different systems, however this is still sufficiently rare that the game should give you fair warning about this.

Other common actions include `SEARCH`, `LOOK UNDER`, `LOOK INSIDE`, `TAKE` and `DROP`. Kleptomania is usually mandatory in IF, so grab all you can. Any given game will certainly allow you to do more than just this: part of the fun of IF is working out what you can do in a game. It's common to be able to `LOOK UP` things in books; `TALK TO` other characters; `PUT` items on, in or under other items; `OPEN` or `CLOSE` bags, boxes and doors; `PUSH` things around; `SWITCH` things on and off; and more. You will almost certainly have to experiment: try to phrase what you want to do as a command, and see if the game understands you.

You may encounter other characters in a game - you can usually interact with these. The conventional methods are `Character, COMMAND` (which orders a character to do something), `ASK Character ABOUT Subject` (which consults a character about something), `TELL Character ABOUT Subject` and `ANSWER Something TO Character` (which responds to a question). `TALK TO Character` has also become popular in recent times: usually this will give you a menu-based conversation system.

Some very common commands can be abbreviated. In particular, `LOOK` can usually be abbreviated to `L`, `INVENTORY` to `I` and you should be able to move around by typing abbreviating the directions to `N, E, S, W, NE, NW, SE, SE` - so `NORTH` or `N` will move you north.

Usually there are some 'meta' commands, which don't actually affect the player character in the game, but rather provide you information, or control particular aspects of the game. Games will usually provide a `QUIT` command to leave the game, a `SAVE` command to save the game state, a `RESTORE` command to restore it again, an `UNDO` command to undo your last move, a `SCORE` and `FULL` command to check your progress and `RESTART` to give up on your current game and start again. A good game will also provide a command that will provide access to an online manual or description of the game. The name of this command varies and is not always present, but common choices are `HELP`, `ABOUT` or `MANUAL`. Some games provide an on-line hint system with the `HINTS` or `HINT` command.

## Example game

This is a transcript from a made-up game. It illustrates possible single scene in a science fiction work. Commentary is in italics.

Tundra
While StarCommand were typically vague of the details, you imagine the strange blue rocks and pink sky might have something to do with the research station you're supposed to be investigating. Most of the planets you visit seem to have odd colour schemes, though.
A dragon is chewing on the remains of your security team. Your No'I'Tal science officer is cowering behind a rock.

[ Well, here we are on a fairly standard planet. As per tradition, your security team has been killed by a monster. I suppose we should try and do something about it. ]

> x dragon
Not the cliched fire-breathing beast of myth, but a large reptile indigenous to this planet. The No'I'Tal assures you that this species is herbivorous and harmless. Those large teeth are merely for chewing up the tough bark of the native trees.
This is certainly an impressive beast: its silver hide glitters despite the dim sunshine, and the point of each of its dorsal spines is a miniature nova. Its dark brown eyes contrast markedly to its brilliant skin.
Thorough research is vital to the success of any mission, or so says the StarCommand leadership manual. You really must press this point home to your science officer one day. Right after you've reprimanded him for cowardice.

[ Dragons are a bit of a cliche in IF. Fortunately, this is merely a native of this particular planet... It seems your science officer isn't much good at his job. 'x' is a common abbreviation for 'examine' - descriptions of things are often important and can contain vital clues. Sometimes you can 'look further' into an object - inspecting its parts. ]

> x science officer
You can't presently get a good look at him, because he's cowering behind a rock and making whimpering noises. Good crewmen are so hard to find.
The dragon happily crunches its way through a bone.
> i
You are carrying:
A SureKil MkII blaster
A yellow jumper (ripped) (worn)
A communicator (smashed)

[ Your inventory... Maybe we could just shoot our way out of this one... ]

> shoot dragon
(with the SureKil MkII blaster)
Well, it's always worth a second go. As before, the dragon's thick mirror hide reflects the gun's particle beam, which bounces off and demolishes a rock. Coincidentally, this is the rock that your good-for-nothing science officer is hiding behind. At least you didn't get your shirt ripped this time around.
The dragon purrs contentedly and warms itself on the remains of the rock, as your science officer dances around looking for another rock to hide behind.

[ Oh dear, this dragon is laser-proofed. Well, particle-beam proofed, but it's all the same to you. No easy answers here... ]

> x blaster
Standard StarCommand issue, made of cheap plastic. A small dial on top allows you to set the power level of the blaster. The dial is currently set to 8 - Kill with Extreme Prejudice.
Your science officer climbs a tree, and attempts to conceal himself in the foliage.

[ Aha! The blaster has different power levels... Maybe if we increase the power ]

> set dial to 11
You've always wanted a blaster that goes to 11. But StarCommand believe in cost cutting, and your salary is not enough to buy one. This blaster only goes to 9.
A squadron of bat-like creatures barrel out of the tree, closely followed by your science officer (who lands on his head, damaging nothing important).
> set dial to 9
You set the dial to 9, overload.
> shoot dragon with blaster
The blaster overloads and explodes, detonating it's antimatter core. This kills the dragon, and for an extra bonus, all the potentially hostile wildlife within a mile. In a final buy-two-get-one-free offer, it also vapourises you. SureKil really do give very good value.
*** You have died ***
In that game you scored 20 out of a possible 500, in 94 turns, giving you the rank of Aberrant Astronaut.

[ Oh dear, it blew up in our face. Oh well, we can always undo a turn... ]

Would you like to RESTART, RESTORE a saved game, give the FULL score for that game, or QUIT?
> undo
Tundra
[Previous turn undone.]
> x science officer
Ah yes, your esteemed colleague. He is a No'I'Tal, a green biped with an exceptionally large head. This is his first mission on your ship - he joined as part of an exchange scheme - your regular science officer is currently serving on a No'I'Tal ship. The No'I'Tal have a reputation for their photographic memories, which has not been borne out by your science officer's recent performance.
The dragon gulps down the remainder of your security team, and starts to sniff around. You sidle around to its rear end and hope it can't smell you.
> ask science officer about dragon
"I-I-I w-was sure that it was harmless", he stammers, "M-maybe our records are i-incorrect. It's s-strange that its skin is able to reflect p-particle beams, though."
The dragon snuffles on the ground, the sun sparkling from the scales on its head.

[ Sometimes asking other characters ('NPCs') about things can give you a clue. The science officer isn't much use while he's so nervous, though ]

> x tree
The trees are pink, almost matching the sky. Their foliage (also pink) is sparse, but the individual leaves are very large, presumably to catch as much as possible of the little sun that filters through the hazy sky.
The dragon raises its head and sniffs the air, and slowly begins to lumber around, a reflection from a dorsal spine briefly dazzling you. You cautiously stay behind it.

[ Recall that our scientific friend tried to climb a tree earlier on... Maybe that was a clue (but, maybe not). The dragon is definitely getting restless, however. ]

> x dragon
Not the cliched fire-breathing beast of myth, but a large reptile indigenous to this planet. The No'I'Tal once assured you that this species is herbivourous and harmless. It turns out that those large teeth are used for chewing bone.
This is certainly an impressive beast: its silver hide glitters despite the dim sunshine, and the point of each of its dorsal spines is a miniature nova. Its dark brown eyes contrast markedly to its brilliant skin.
The dragon sniffs at a shard of rock.

[ Maybe there's a clue in the dragon's description... Hmm, it specifically mentions spines, and the head was mentioned earlier on... ]

> x dragon's spines
Each spine is a foot long, and as reflective as the rest of the beast's skin. They project from the creature's back and tail. Somehow, a bright point of light appears to shine from the tip of each spine.
The dragon nibbles the rock to see if it's edible. It's not.
> x dragon's head
Two dark eyes glower from a silver head. The eyes are well protected from attack by ridges and spines. Any animal trying to claw this creature's eyes out would probably impale its own claws.
The dragon lifts it's head and peers around. You attempt to duck out of sight, and hope it hasn't seen you.
> x dragon's eyes
The dragon has two dark brown eyes, positioned either side of its snout. A spine projects above each eye, with ridges underneath to prevent gouging.
The dragon rubs against a tree, dislodging some loose scales.

[ Ah, its eyes - they aren't reflective... Maybe we could shoot them out ]

> set blaster to 6
You set the dial to 6, Kill Politely

[ Don't want the blaster to blow up in our face again... ]

> shoot dragon's eyes
You carefully aim your blaster at one of the dragon's eyes and pull the trigger. The creature roars in pain, and, aiming its one good eye at you, begins to lumber around to swipe at you. Now the dragon is moving, it's hard to aim the particle beam at its remaining eye. You hold down the trigger and hope, the beam scattering across the landscape and roasting assorted trees and rocks. The dragon eventually completes it's turn and begins to charge, as your reflected beam devastates the landscape around you. At the last minute, you step aside, and aim the blaster square into the dragon's remaining eye; it screams and charges headlong into the one remaining tree, knocking itself out cold. Your blaster emits a final, pathetic noise and dies in your hand.
Glancing around, you see that your science officer has disappeared. The low setting of your blaster wouldn't have vapourised him, so he has probably run off somewhere. You sigh - you're going to have to find him. You need him to swap back for your original officer.

[ Woo, we have slain the dragon, or knocked it unconcious, at any rate. The observant out there will have noticed that the dragon lost a few of its scales earlier on, but we're not being observant, so we're going straight to look for our missing science officer ]

>n
Tundra
The landscape of this planet doesn't change much. Blue rocks and pink trees seem to be just about all it has to look at. The ones around here are covered in burn marks, apparently caused by a blaster.
>

[ Here is where our example ends... If this were an actual game, you would now need to find the science officer, and at some point get round to investigating that research lab ]

Zoom written by Andrew Hunter. Mail any suggestions, bug reports or abuse to andrew@logicalshift.demon.co.uk