jrflga / cofree-bot

A library for building bots compositionally.

cofree-bot

cofree-bot is a toolkit for building chat bots compositionally. Bots can be defined over arbitrary inputs or outputs, combined together and then "lifted" to operate in any context.

Supported Chat Protocols:

• Matrix
• Zulip (in progress)
• CLI REPL

The Bot type

data BotAction s o = BotAction { responses :: o, nextState :: s }
newtype Bot m s i o = Bot { runBot :: i -> s -> m (BotAction s o) }

Building bot behaviors

helloWorldBot :: Applicative m => Bot m () T.Text T.Text
helloWorldBot = Bot $ \input state ->
  let output = "Hello " <> input
  in pure $ BotAction output state

Lifting Bots Over more complex inputs and outputs

matrixHelloBot :: Bot IO () (RoomID, Event) (RoomID, Event)
matrixHelloBot = second' $ dimap viewBody mkMsg helloWorldBot
  where
    viewBody :: Event -> T.Text
    viewBody = (view (_EventRoomMessage . _RoomMessageText . _mtBody))

    mkMsg :: T.Text -> Event
    mkMsg msg = EventRoomMessage $ RoomMessageText $ MessageText msg TextType Nothing Nothing

Combing Bot Behaviors

combinedBot :: Applicative m => Bot m () (Either T.Text Int) (Either T.Text Int)
combinedBot = helloWorldBot \/ calculatorBot