miniMax Algorithm in Elm - Tests - next move wins - Implementation 3 - With Fold

Scorer.elm

module Scorer exposing (..)

import Array exposing (fromList, get, map, set)
import List exposing (foldl, map)
import Maybe exposing (withDefault)


markerX : Char
markerX =
    'X'

empty : Char
empty =
    ' '

nextBestMove : List (List Char) -> Int
nextBestMove gameNode =
    let
        node =
            List.map fromList gameNode

        currentBoard =
            fromList node

        row1 =
            get 0 currentBoard

        row1NextState =
            set 2 markerX (withDefault (Array.initialize 3 (always empty)) row1)

        row2 =
            get 1 currentBoard

        row2NextState =
            set 2 markerX (withDefault (Array.initialize 3 (always empty)) row2)
    in
    if winnerFound row1NextState then
        2
    else if winnerFound row2NextState then
        5
    else
        0


markerFound : Char -> Array.Array Char -> Array.Array Bool
markerFound marker row =
    Array.map (\cell -> cell == marker) row


winnerFound : Array.Array Char -> Bool
winnerFound row =
    Array.foldl (\wasFound found -> wasFound == found) True (markerFound markerX row)