comment-beside-a-wildcard-out.hs

{-# LANGUAGE PatternSynonyms #-}

-- A comment written beside the wildcard of an item stays inside its
-- parentheses.
module Ledger.Entry
  ( Entry ({- fields too -} ..),
    Side (Debit, {- and the rest -} ..),
    total,
  )
where

import Ledger.Money (Money (.. {- abstract upstream -}), add)

data Entry = Entry{entrySide :: Side, entryAmount :: Money}

data Side = Debit | Credit

total :: [Entry] -> Money
total = foldr (add . entryAmount) mempty