{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}

module Hcompta.Lib.Consable where

-- import Control.Applicative (Const(..))
import Data.Function (id)
-- import Data.Functor.Compose (Compose(..))
import Data.Monoid (Monoid(..))
import Data.Ord (Ord(..))
import qualified Data.Map.Strict as Map
import Data.Map.Strict (Map)

class Consable x m where
	mcons :: x -> m -> m

instance Consable x () where
	mcons _x = id
instance Consable x [x] where
	mcons = (:)

instance (Monoid v, Ord k) => Consable (k, v) (Map k v) where
	mcons (k, v) = Map.insertWith mappend k v

{-
instance Monoid (f (g x)) => Monoid ((Compose f g) x) where
	mempty = Compose mempty
	mappend (Compose x) (Compose y) = Compose (mappend x y)
-}