-- |
-- subset of the same file in src/ directory. So I don't have to expose it.
{-# LANGUAGE RecursiveDo #-}

module Reflex.Potato.Helpers
  ( foldDynMergeWith
  , getLeft
  , getRight
  )
where

import           Relude

import           Reflex

import           Control.Monad.Fix

import qualified Data.Dependent.Map as DM
import qualified Data.Dependent.Sum as DS


foldDynMergeWith
  :: (Reflex t, MonadHold t m, MonadFix m)
  => b -- ^ initial value of dynamic
  -> [Event t (b -> b)]  -- ^ list of events producing a reducing method
  -> m (Dynamic t b)  -- ^ final output after all folding methods applied
foldDynMergeWith acc = foldDyn ($) acc . mergeWith (.)


getLeft :: Either a b -> Maybe a
getLeft (Left x) = Just x
getLeft _        = Nothing

getRight :: Either a b -> Maybe b
getRight (Right x) = Just x
getRight _         = Nothing