src/Literate/Accounting/Move.hs

   1 module Literate.Accounting.Move where
   2
   3 import GHC.Stack (HasCallStack)
   4 import Data.Function ((.))
   5 import Literate.Accounting.Math
   6 import Literate.Accounting.Unit
   7 import Literate.Accounting.Chart
   8
   9 {-
  10 data Account = Account
  11 data Amount qty = Amount
  12   { amountUnit :: Unit
  13   , amountQuantity :: qty
  14   }
  15 instance Negable qty => Negable (Amount qty) where
  16   negate Amount{..} = Amount{ amountQuantity = negate amountQuantity, ..}
  17 -}
  18
  19 type family AmountOf a
  20 type family AccountOf a
  21 type family AccountSectionOf a
  22
  23 type instance AmountOf [a] = AmountOf a
  24 type instance AccountOf [a] = AccountOf a
  25 type instance AccountSectionOf [a] = AccountSectionOf a
  26
  27 -- * Class 'Postable'
  28 -- class Postable post where
  29   -- post :: HasCallStack => AccountOf post -> AmountOf post -> post
  30
  31 class Postable acct unit qty post where
  32   (+=) ::
  33     HasCallStack =>
  34     Postable acct unit qty post =>
  35     Account acct -> Amounts unit qty -> post
  36   infixr 4 +=
  37
  38 (-=) ::
  39   HasCallStack =>
  40   Postable acct unit qty post =>
  41   Negable qty =>
  42   Account acct -> Amounts unit qty -> post
  43 (-=) acct = (+=) acct . negate
  44 infixr 4 -=