63 lines
3.4 KiB
Org Mode
63 lines
3.4 KiB
Org Mode
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* Fatal Distractions Chapter 1 - Text Adventures
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** Concept
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I'm not looking for anything super complicated. I've spent maybe 90 minutes
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in my life playing text adventures, I'm sure there are some with really good
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mechanics. For this one, I'm aiming for something at about the level of
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[[https://homestarrunner.com/dungeonman][Thy Dungeonman]]. A map, moving between rooms, getting items, <verb>ing <item>s
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<preposition> <other item>s. If I'm pretty much finished before the end of the
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month, I could add
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- visual effects
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- saving and loading
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- pictures
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- music
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I'm not trying to be a purist about this; I know 99% of all text adventures are
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*just* text, but music is also fun to put together.
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** Implementation
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*** Flags
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A flag is a combination name and uinteger value. The value can be changed as the
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result of an action, or checked within a predicate. Three uses for these:
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- Boolean values, 1 or 0
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- Countdowns, start at some positive value and eventually become 0 = false
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- Counters, start at zero and increment ("you have rung the bell 10 times")
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Counters seem really optional, booleans and countdowns seem actually useful.
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Values should evaluate to false if zero, true otherwise.
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Effects should be able to enable (set to 1), disable (set to 0), increment, or
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decrement; if there's need for it, they'll need to set (set to X), I don't think so.
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*** Effects
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When an action evaluates, most of the time it will have no effect ("you can't
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go north from here"). Sometimes though, an action should change the world. Here
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are some effects:
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- Modify a flag (detailed above)
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- Change the current room
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- Add / remove an item from the inventory
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- Do some meta thing (save or load)
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*** Predicates
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I guess I need a DSL for predicates. I don't think I'll need to implement "OR",
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my predicates should be able to be a chain of clauses "AND"ed together. Some clauses:
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- IN(room_name), true if the current room has that name
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- HAS(item_name), true if that item is in the inventory (or in the room)
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- ENABLED(flag_name), true if that flag has a value > 0
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- TO(item_name), this is the real tough one, for transitive verbs with an object
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- 'use key on door'
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- 'give trinket to dennis'
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- 'take torch from sconce'
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Some of these things are items, some are definitely not. Not sure how to codify. Maybe:
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- DITRANSITIVE(preposition, object), which checks that the command is of the form:
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<verb> <noun> <preposition> <object>
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- Even monotransitive verbs ("pull lever") need to specify what they'll act on.
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*** Actions
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Actions are a command, or part of a command, plus a predicate, plus a priority,
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plus a description, plus (optionally) some effects:
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PULL | * | 1 | You don't see anything to pull |
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PULL | IN(lever_room) | 10 | What do you want to pull? |
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PULL LEVER | IN(lever_room) | 100 | You pull the lever. Nice. | ENABLE(lever_pulled)
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PULL LEVER | IN(lever_room) & ENABLED(lever_pulled) | 1000 | You already pulled it. |
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If the command matches all of the first column, it looks at that action.
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">PULL LEVER" would match all four, ">PULL" would only match the first two.
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The game would choose between all matched actions, filter to only the ones whose
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predicates are fulfilled, and choose from those the one with the highest priority.
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This might require a lot of typing, but I think it will have enough flexibility
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to do everything I might want to do.
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