From 5eaa0cf7eaef1a58be0f13c1273971bb118aa143 Mon Sep 17 00:00:00 2001
From: Neil Smith <neil.git@njae.me.uk>
Date: Thu, 13 Dec 2018 14:41:25 +0000
Subject: [PATCH] Started day 13

---
 src/advent13/advent13.hs | 63 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 src/advent13/advent13.hs

diff --git a/src/advent13/advent13.hs b/src/advent13/advent13.hs
new file mode 100644
index 0000000..354d24a
--- /dev/null
+++ b/src/advent13/advent13.hs
@@ -0,0 +1,63 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+
+import Data.List
+import qualified Data.Set as S
+
+data Cell = Empty | Horizontal | Vertical | Clockwise | Anticlockwise | Junction deriving (Show, Eq)
+data Direction = Up | Right | Down | Left deriving (Show, Eq, Ord, Enum, Bounded)
+
+main :: IO ()
+main = do 
+    text <- TIO.readFile "data/advent12.txt"
+    let (initial, rules) = successfulParse text
+    let row = makeWorld 0 initial
+    print $ part1 rules row
+    print $ part2 rules row
+
+
+
+-- Move in the current direction
+takeStep :: Direction -> Cell -> Int -> Int -> (Direction, Int, Int)
+takeStep Up x y = (x, y-1)
+takeStep Down x y = (x, y+1)
+takeStep Left x y = ( x-1, y)
+takeStep Right x y = (x+1, y)
+
+
+-- | a `succ` that wraps 
+turnCW :: (Bounded a, Enum a, Eq a) => a -> a 
+turnCW dir | dir == maxBound = minBound
+           | otherwise = succ dir
+
+-- | a `pred` that wraps
+turnACW :: (Bounded a, Enum a, Eq a) => a -> a
+turnACW dir | dir == minBound = maxBound
+            | otherwise = pred dir
+
+
+
+-- Parse the input file
+
+type Parser = Parsec Void Text
+
+sc :: Parser ()
+sc = L.space (skipSome spaceChar) CA.empty CA.empty
+
+symb = L.symbol sc
+potP = (char '.' *> pure False) <|> (char '#' *> pure True)
+
+initialPrefix = symb "initial state:"
+ruleSepP = symb "=>"
+
+fileP = (,) <$> initialP <*> many ruleP
+initialP = initialPrefix *> many potP <* sc
+ruleP = Rule <$> ruleLHS <* ruleSepP <*> ruleRHS
+ruleLHS = count 5 potP <* sc
+ruleRHS = potP <* sc
+
+successfulParse :: Text -> ([Bool], [Rule])
+successfulParse input = 
+        case parse fileP "input" input of
+                Left  _error -> ([], []) -- TIO.putStr $ T.pack $ parseErrorPretty err
+                Right world -> world
-- 
2.34.1