Haskell solution of Advent of Code 2023 day 3

day3.hs

{-# LANGUAGE TypeApplications #-}
import Data.Char
import Data.Bifunctor (second)
import Data.Function
import Data.List

main = interact $  solution . lines

map3 f (a,b,c) = (f a, f b, f c)

splitMiddle ((a,b,c),(d,mid,f),(g,h,i)) = (mid, [a,b,c,d,f,g,h,i])

solution lns = 
  show . sum . concat 
  . map ( map (read @Int . map fst)
        . filter (any snd) 
        . filter (isDigit.fst.head) 
        . groupBy ((==) `on` (isDigit.fst)) 
        . (map.second) (any isValidSymbol) 
        )
  . getNeighbors $ lns

getNumber xs = (map fst xs, any snd xs)

getNeighbors = map (map splitMiddle) . neighborLines . map neighborCols
filler = repeat ('.','.','.')
neighborLines lns = zipWith3 zip3 (filler : lns) lns (tail lns ++ [filler])
neighborCols line = zip3 ('.' : line) line (tail line ++ ".")

isValidSymbol c = c /= '.' && not (isDigit c)