src/Symantic/Compta/Input/Chart.hs

   1 module Symantic.Compta.Input.Chart where
   2
   3 import Control.Applicative (Applicative(..))
   4 import Control.Monad (Monad(..))
   5 import Data.Foldable (foldr)
   6 import Data.Functor (Functor)
   7 import Data.Monoid (Monoid(..))
   8 import Data.Ord (Ord(..))
   9 import Data.Semigroup (Semigroup(..))
  10 import Prelude (error)
  11 import qualified Control.Monad.Trans.Writer as MT
  12 import qualified GHC.Exts as GHC
  13
  14 import Symantic.Compta.Lang.Rebindable
  15 import Symantic.Compta.Lang
  16 import Symantic.Compta.Calc.Chart
  17
  18 -- * Type 'ChartM'
  19 -- | A 'Monad' to construct a 'Chart'.
  20 newtype ChartM k v m a = ChartM { unChartM ::
  21   MT.WriterT (v, Chart k v) m a
  22   } deriving newtype (Functor, Applicative, Monad)
  23
  24 runChartM :: Monad m => ChartM k v m a -> m (Chart k v)
  25 runChartM chM = do
  26   (_a, (_v, ch)) <- MT.runWriterT (unChartM chM)
  27   return ch
  28
  29 instance (Ord k, Monoid v, Monad m) => Semigroup (ChartM k v m a) where
  30   (<>) = (Control.Monad.>>)
  31 instance (Ord k, Monoid v, Monad m, Monoid a) => Monoid (ChartM k v m a) where
  32   mempty = return mempty
  33 instance
  34   ( Ord k
  35   , Monoid v
  36   , Monad m
  37   , Monoid a
  38   ) => GHC.IsList (ChartM k v m a) where
  39   type Item (ChartM k v m a) = ChartM k v m a
  40   fromList = mconcat
  41   fromListN _n = mconcat
  42   toList = return