Advent of Code - Day 3 Part 1

day3Part1.hs

import Data.List (group, sort)
import Text.Trifecta

data FabricRect = FabricRect { fId :: Integer
                             , fWidth :: Integer
                             , fHeight :: Integer
                             , fX :: Integer
                             , fY :: Integer
                             } deriving (Show)

parseFabric :: Parser FabricRect
parseFabric = do
    _ <- char '#'
    fId <- integer
    _ <- string "@ "
    fX <- integer
    _ <- char ','
    fY <- integer
    _ <- string ": "
    fWidth <- integer
    _ <- char 'x'
    fHeight <- integer

    return $ FabricRect fId fWidth fHeight fX fY

getFabrics :: FilePath -> IO (Result [FabricRect])
getFabrics path = do
    inputData <- lines <$> readFile path
    return $ sequence 
           $ parseString parseFabric mempty <$> inputData

getPoints :: FabricRect -> [(Integer, Integer)]
getPoints (FabricRect _ w h xPos yPos) = [(x,y) | x <- [xPos..xPos+w-1], y <- [yPos..yPos+h-1]]

solve :: FilePath -> IO ()
solve p = do
    fs <- getFabrics p
    case fs of
        Success fs -> print $ length $ filter (\x -> length x > 1) . group . sort $ foldMap getPoints fs
        _          -> print "failed to parse"