Configurable inputs in model (Elm 0.13) - keyboard

Question

For an Elm (0.13) game I'm developing, I'd like to have reconfigurable inputs. A simplified version of the model that I've got for this is
type Controls = {
up: KeyCode,
down: KeyCode,
left: KeyCode,
right: KeyCode
}
type Player = {
...
controls: Controls,
...
}
type Game = {
state: State,
players: [Player]
}
For the game loop, I'm using a standard foldp construction, where I'd like the input to be dependent of the current state of the game. So far I tried the following:
gameState =
let
initialGame = (newGame initialActive)
in
foldp update initialGame (input initialGame)
but of course, the input signal generating function (input : Game -> Signal Input) keeps on using the initial game, and not the changed gamestate.
I've searched troughout the internet to find a solution to this, but I couldn't find anything in this direction. Is there a way to do it the way I was trying (by including the controls in the model), or will I have to release the controls from the model by making the controls signals themselves?

Answer 1

There is a closely related question here: Creating custom keyboard controls [Elm]
If you want to, you can keep the Controls part of your game state. The way to do this is not to base your input on the initialGame, but to take more general input from which you can always extract what you need. In this case that would be Keyboard.keysDown. Then you can get the input for each player using:
playerInput : Controls -> [KeyCode] -> { x : Int, y : Int }
playerInput {up,down,left,right} kd =
List.filter (\ky -> List.member ky [up,down,left,right]) kd |>
List.foldl (\ky st -> if | ky == up -> { st | y <- st.y + 1 }
| ky == down -> { st | y <- st.y - 1 }
| ky == left -> { st | x <- st.x - 1 }
| ky == right -> { st | x <- st.x + 1 }
) {x=0,y=0}
If you want to remove Controls from Game you can hoist it up into the definition of the input for the foldp.