Adds types, and read-show functions

app/Main.hs

@@ -1,6 +0,0 @@
-module Main where
-
-import Lib
-
-main :: IO ()
-main = someFunc

package.yaml

@@ -14,23 +14,19 @@ description:         Please see the README on GitHub at <https://github.com/abhi
 dependencies:
 - base >= 4.7 && < 5
 
-library:
-  source-dirs: src
-
 executables:
   hasdoku:
-    main:                Main.hs
-    source-dirs:         app
+    main:                Sudoku.hs
+    source-dirs:         src
     ghc-options:
     - -threaded
     - -rtsopts
     - -with-rtsopts=-N
     dependencies:
-    - hasdoku
+    - split
 
 tests:
   hasdoku-test:
     main:                Spec.hs
     source-dirs:         test
-    dependencies:
-    - hasdoku
+    dependencies: []

src/Lib.hs

@@ -1,6 +0,0 @@
-module Lib
-    ( someFunc
-    ) where
-
-someFunc :: IO ()
-someFunc = putStrLn "someFunc"

src/Sudoku.hs

@@ -0,0 +1,39 @@
+module Main where
+
+import qualified Data.Char
+import qualified Data.List.Split
+import qualified Data.List
+
+data Cell = Fixed Int | Possible [Int] deriving (Show, Eq)
+type Row  = [Cell]
+type Grid = [Row]
+
+possibleVals :: Cell -> [Int]
+possibleVals (Fixed x)     = [x]
+possibleVals (Possible xs) = xs
+
+readGrid :: String -> Maybe Grid
+readGrid s = if length s /= 81
+  then Nothing
+  else sequence . map (sequence . map readCell) . Data.List.Split.chunksOf 9 $ s
+  where
+    readCell '.' = Just $ Possible [1..9]
+    readCell c
+      | Data.Char.isDigit c && c > '0' = Just . Fixed . Data.Char.digitToInt $ c
+      | otherwise = Nothing
+
+showGrid :: Grid -> String
+showGrid = unlines . map (unwords . map showCell)
+  where
+    showCell (Fixed x) = show x
+    showCell _ = "."
+
+showGridWithPossibilities :: Grid -> String
+showGridWithPossibilities = unlines . map (unwords . map showCell)
+  where
+    showCell (Fixed x)     = show x ++ "          "
+    showCell (Possible xs) =
+      (Data.List.foldl' (\acc x -> acc ++ if x `elem` xs then show x else " ") "[" [1..9]) ++ "]"
+
+
+main = undefined