[Haskell-cafe] Re: Haskell shootout game

[apfelmus]

Hugh Perkins wrote:
> Had an idea: a real shootout game for Haskell.
>
> scripts "fight" in an arena for a second or so, and the results are
> published to the website

Sounds great :)

There are lots of "robot battle" games out there, like

  http://realtimebattle.sourceforge.net/
  http://robocode.sourceforge.net

but none in Haskell, of course. I think there's a classic predecessor to
those but I don't know exactly.

> Each turn is represented by a function something like:
> 
> doturn :: String -> [[GridValue]] -> (Action,String)

The explicit state can be dispensed with by introducing a stream type

  data Robot = Robot (BattleField -> (Action, Robot)

  type BattleField = [[GridValue]]

This way, the program is entirely free in how to choose its state
representation. You can turn any  doturn - based program into a
stream-based one

  toRobot :: String -> (BattleField -> String -> (Action,String))
            -> Robot
  toRobot s doturn = Robot $ \arena ->
     let (action, s') = doturn bf s in (action, toRobot s' doturn)

The drawback is that it's no longer possible to save a snapshot of each
program's state to disk and resume the fight later.

Regards,
apfelmus