Day8 partial input parsing.

1 files changed, 41 insertions, 0 deletions

diff --git a/Day8/app/Main.hs b/Day8/app/Main.hs
new file mode 100644
index 0000000..fc36d66
--- /dev/null
+++ b/Day8/app/Main.hs
@@ -0,0 +1,41 @@
+module Main (main) where
+
+import System.Environment ( getArgs )
+
+main :: IO ()
+main = getArgs >>= readFile . head >>= print . solveDay8
+
+solveDay8 :: String -> String
+solveDay8 = formatDay8Result . fmap solveDay8Parts . parseDay8Input
+
+formatDay8Result :: Maybe (Int, Int) -> String
+formatDay8Result Nothing = "Input didn't parse. Check that it is a rectangular grid with values from 0-9."
+formatDay8Result (Just (p1, p2)) = "Part 1: " ++ show p1 ++ ", Part 2: " ++ show p2
+
+newtype Day8Input = Day8Input [[Height]] -- but with guarantee that it's rectangular
+
+data Height = Zero | One | Two | Three | Four | Five | Six | Seven | Eight | Nine
+    deriving (Eq, Ord)
+
+heightFromChar :: Char -> Maybe Height -- this could also be done using the Enum typeclass' toEnum function and an intermediate Int
+heightFromChar '0' = Just Zero
+heightFromChar '1' = Just One
+heightFromChar '2' = Just Two
+heightFromChar '3' = Just Three
+heightFromChar '4' = Just Four
+heightFromChar '5' = Just Five
+heightFromChar '6' = Just Six
+heightFromChar '7' = Just Seven
+heightFromChar '8' = Just Eight
+heightFromChar '9' = Just Nine
+heightFromChar _ = Nothing
+
+validateDay8Input :: [[Height]] -> Maybe Day8Input
+validateDay8Input [] = Nothing
+validateDay8Input (h:hs) = if all ((== length h) . length) hs then Just $ Day8Input $ h:hs else Nothing
+
+parseDay8Input :: String -> Maybe Day8Input
+parseDay8Input = (=<<) validateDay8Input . mapM (mapM heightFromChar) . lines
+
+solveDay8Parts :: Day8Input -> (Int, Int)
+solveDay8Parts = undefined
\ No newline at end of file