hjugement-protocol/src/Voting/Protocol/Utils.hs

   1 module Voting.Protocol.Utils where
   2
   3 import Control.Applicative (Applicative(..), Alternative(..))
   4 import Control.Monad (Monad(..), join, mapM, unless, zipWithM)
   5 import Control.Monad.Trans.Class (MonadTrans(..))
   6 import Data.Bool
   7 import Data.Either (either)
   8 import Data.Eq (Eq(..))
   9 import Data.Foldable (Foldable, foldMap, and, sequenceA_)
  10 import Data.Function (($), id, const)
  11 import Data.Functor (Functor, (<$>), (<$))
  12 import Data.Functor.Identity (Identity(..))
  13 import Data.Maybe (Maybe(..), maybe)
  14 import Data.Traversable (Traversable(..))
  15 import qualified Data.List as List
  16
  17 -- | NOTE: check the lengths before applying @f@.
  18 isoZipWith :: (a->b->c) -> [a]->[b]->Maybe [c]
  19 isoZipWith f as bs
  20  | List.length as /= List.length bs = Nothing
  21  | otherwise = Just (List.zipWith f as bs)
  22
  23 -- | NOTE: check the lengths before applying @f@.
  24 isoZipWith3 :: (a->b->c->d) -> [a]->[b]->[c]->Maybe [d]
  25 isoZipWith3 f as bs cs
  26  | al /= List.length bs = Nothing
  27  | al /= List.length cs = Nothing
  28  | otherwise = Just (List.zipWith3 f as bs cs)
  29  where al = List.length as
  30
  31 isoZipWithM ::
  32  Applicative m =>
  33  m () ->
  34  (a -> b -> m c) ->
  35  [a] -> [b] -> m [c]
  36 isoZipWithM err f as bs =
  37         maybe ([] <$ err) sequenceA $
  38                 isoZipWith f as bs
  39
  40 isoZipWithM_ ::
  41  Applicative m =>
  42  m () ->
  43  (a -> b -> m c) ->
  44  [a] -> [b] -> m ()
  45 isoZipWithM_ err f as bs =
  46         maybe err sequenceA_ $
  47                 isoZipWith f as bs
  48
  49 isoZipWith3M ::
  50  Applicative m =>
  51  m () ->
  52  (a -> b -> c -> m d) ->
  53  [a] -> [b] -> [c] -> m [d]
  54 isoZipWith3M err f as bs cs =
  55         maybe ([] <$ err) sequenceA $
  56                 isoZipWith3 f as bs cs
  57
  58 isoZipWith3M_ ::
  59  Applicative m =>
  60  m () ->
  61  (a -> b -> c -> m d) ->
  62  [a] -> [b] -> [c] ->
  63  m ()
  64 isoZipWith3M_ err f as bs cs =
  65         maybe err sequenceA_ $
  66                 isoZipWith3 f as bs cs
  67