lib/Hcompta/Format/Ledger/Balance.hs

   1 {-# LANGUAGE NamedFieldPuns #-}
   2 module Hcompta.Format.Ledger.Balance where
   3
   4 import           Hcompta.Model (Transaction)
   5 import qualified Hcompta.Calc.Balance as Balance
   6 import qualified Hcompta.Format.Ledger.Journal as Journal
   7 import           Hcompta.Format.Ledger.Journal (Journal(..))
   8 import qualified Hcompta.Lib.Foldable as Lib.Foldable
   9
  10 -- * The 'Balance.Deviation' type
  11
  12 -- | Return the first 'Transaction' (if any) whose 'Posting's
  13 --   do not sum to a 'Balance' respecting 'Balance.is_inferrable',
  14 --   with the path of 'Journal's leading to that 'Transaction'.
  15 check_equilibrium :: Journal -> Maybe ((Transaction, Balance.Deviation), [Journal])
  16 check_equilibrium =
  17         Journal.find
  18          (\Journal{Journal.transactions} ->
  19                 Lib.Foldable.find
  20                  (Lib.Foldable.find
  21                          (\tr -> do
  22                                 let bal = Balance.transaction tr Balance.nil
  23                                 let dev = Balance.deviation bal
  24                                 if Balance.is_equilibrium_inferrable dev
  25                                         then Nothing
  26                                         else Just (tr, dev)
  27                          )
  28                  )
  29                  transactions
  30          )