Write an IntMap module to clean up indexed access code.

src/CacheSim/IntMap.elm

@@ -0,0 +1,30 @@
+module CacheSim.IntMap exposing (..)
+
+type alias IntMap a = List a
+
+intMapGet : Int -> IntMap a -> Maybe a
+intMapGet i m =
+    case (i, m) of
+        (_, []) -> Nothing
+        (0, (x::xs)) -> Just x
+        (n, (x::xs)) -> intMapGet (n-1) xs
+
+intMapUpdate : Int -> (a -> a) -> IntMap a -> IntMap a
+intMapUpdate i f m =
+    case (i, m) of
+        (_, []) -> []
+        (0, (x::xs)) -> (f x)::xs
+        (n, (x::xs)) -> intMapUpdate (n-1) f xs
+
+intMapPut : Int -> a -> IntMap a -> IntMap a
+intMapPut i v = intMapUpdate i (\_ -> v)
+
+intMapFind : (a -> Bool) -> IntMap a -> Maybe Int
+intMapFind f m =
+    let
+        findHelper n l =
+            case l of
+                [] -> Nothing
+                (x::xs) -> if f x then Just n else findHelper (n - 1) xs
+    in
+        findHelper 0 m