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.Either (Either(..), either)
   6 import Data.Eq (Eq(..))
   7 import Data.Foldable (sequenceA_)
   8 import Data.Function (($), (.))
   9 import Data.Functor ((<$))
  10 import Data.Maybe (Maybe(..), maybe)
  11 import Data.String (String)
  12 import Data.Traversable (Traversable(..))
  13 import Data.Tuple (uncurry)
  14 import qualified Data.Aeson.Internal as JSON
  15 import qualified Data.List as List
  16
  17 -- | Like ('.') but with two arguments.
  18 o2 :: (c -> d) -> (a -> b -> c) -> a -> b -> d
  19 o2 f g = \x y -> f (g x y)
  20 infixr 9 `o2`
  21 {-# INLINE o2 #-}
  22
  23 -- | NOTE: check the lengths before applying @f@.
  24 isoZipWith :: (a->b->c) -> [a]->[b]->Maybe [c]
  25 isoZipWith f as bs
  26  | List.length as /= List.length bs = Nothing
  27  | otherwise = Just (List.zipWith f as bs)
  28
  29 -- | NOTE: check the lengths before applying @f@.
  30 isoZipWith3 :: (a->b->c->d) -> [a]->[b]->[c]->Maybe [d]
  31 isoZipWith3 f as bs cs
  32  | al /= List.length bs = Nothing
  33  | al /= List.length cs = Nothing
  34  | otherwise = Just (List.zipWith3 f as bs cs)
  35  where al = List.length as
  36
  37 isoZipWithM ::
  38  Applicative f =>
  39  f () -> (a->b->f c) -> [a]->[b]->f [c]
  40 isoZipWithM err f as bs =
  41         maybe ([] <$ err) sequenceA $
  42                 isoZipWith f as bs
  43
  44 isoZipWithM_ ::
  45  Applicative f =>
  46  f () -> (a->b->f c) -> [a]->[b]->f ()
  47 isoZipWithM_ err f as bs =
  48         maybe err sequenceA_ $
  49                 isoZipWith f as bs
  50
  51 isoZipWith3M ::
  52  Applicative f =>
  53  f () -> (a->b->c->f d) -> [a]->[b]->[c]->f [d]
  54 isoZipWith3M err f as bs cs =
  55         maybe ([] <$ err) sequenceA $
  56                 isoZipWith3 f as bs cs
  57
  58 isoZipWith3M_ ::
  59  Applicative f =>
  60  f () -> (a->b->c->f d) -> [a]->[b]->[c]->f ()
  61 isoZipWith3M_ err f as bs cs =
  62         maybe err sequenceA_ $
  63                 isoZipWith3 f as bs cs
  64
  65 -- | Copied from 'Data.Aeson''s 'eitherFormatError'
  66 -- which is not exported.
  67 jsonEitherFormatError :: Either (JSON.JSONPath, String) a -> Either String a
  68 jsonEitherFormatError = either (Left . uncurry JSON.formatError) Right
  69 {-# INLINE jsonEitherFormatError #-}