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

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