shonfeder

module EffEx = struct
  (** Register our new effects *)
  type _ Effect.t +=
    | Print_endline : string -> unit Effect.t
    | Read_line : string Effect.t

  (** helpers to perform the effects *)
  let println s = Effect.perform (Print_endline s)
  let readln () = Effect.perform Read_line

shonfeder

Keybase proof

I hereby claim:

• I am shonfeder on github.
• I am shonfeder (https://keybase.io/shonfeder) on keybase.
• I have a public key ASBDCrS3OyOBp9UsG6Hfu6NSm0zYEubj7ErZJjNSRyqe7wo

To claim this, I am signing this object:

shonfeder

maybe(just(_)).
maybe(nothing).

bind(nothing, _, nothing).
bind(just(A), P, M) :- call(P, A, M),
                       maybe(M).

return(X, just(X)).

maybe_div(_,0,nothing) :- !.

shonfeder

 class (Enum a, Bounded a, Eq a) => Cyclical a where
   next :: a -> a
   next a = if a == maxBound then minBound else succ a
   prev :: a -> a
   prev a = if a == minBound then maxBound else pred a

 data Direction = North | East | South | West
     deriving (Show, Enum, Bounded, Eq)

 instance Cyclical Direction

shonfeder

(* either turn left (L) or right (R) 90 degrees, then walk forward the given number of blocks, ending at a new intersection. *)

(* Relative *)
datatype relative_direction = L | R
type distance = int
datatype instruction = Inst of relative_direction * distance

fun dirFromChar c = case c of #"L" => L
                            | #"R" => R