Main.purs

module Main where

import Prelude

import Data.Foldable (class Foldable, foldl)
import Data.Maybe (Maybe(Just, Nothing))

data NonEmpty a = NonEmpty a (Array a)

instance foldableNonEmpty :: Foldable NonEmpty where
    foldl f acc (NonEmpty a as) = case ?somethingThatGivesAMaybe as of
        Just x -> foldl f (f acc a) (NonEmpty x.head x.tail)
        Nothing -> f acc a
    foldr = ?foldr
    foldMap = ?foldMap