gistfile1.hs

{-# LANGUAGE MultiParamTypeClasses, FlexibleContexts #-}

{- -- Has the error:

Matrix.hs:33:49:
    Kind error: `m' is applied to too many type arguments
    In the type `m (Maybe a)'
    In the type `Integer -> m (Maybe a)'
    In the type `Integer -> Integer -> m (Maybe a)'
--}

module Matrix (
    Matrix,
    fromRows,
    toList,
    toListWithPos,
    toRows,
    rows,
    columns,
    at,
    neighbours,
    neighbourMap
  ) where

import Data.Maybe (catMaybes)

class Matrix m
  where
    -- required
    fromRows       :: [[a]] -> m
    rows           :: m   -> Integer
    columns        :: m   -> Integer
    at             :: m   -> Integer -> Integer -> a

    -- defaults
    toList         :: m -> [a]
    toListWithPos  :: m -> [(Integer, Integer, a)]
    toRows         :: m -> [[a]]
    row            :: m -> Integer -> [a]
    column         :: m -> Integer -> [a]
    vicinityRows   :: m -> Integer -> Integer -> [[Maybe a]]
    vicinityMatrix :: m -> Integer -> Integer -> m (Maybe a)
    neighbours     :: m -> Integer -> Integer -> [a]
    neighbourMap   :: (a -> [a] -> a) -> m -> m