haskell/yesod
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

yesod-form: Add Monad AForm instance for transformers >=0.6

Browse Source 
This is required in order to have a MonadTrans instance
This commit is contained in:
Teo Camarasu 2023-02-07 10:48:42 +00:00
parent 66bed05d33
commit 06fd5df137
1 changed files with 12 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
yesod-form/Yesod/Form/Types.hs
View File

@ -166,6 +166,18 @@ instance Monad m => Applicative (AForm m) where
(a, b, ints', c) <- f mr env ints (a, b, ints', c) <- f mr env ints
(x, y, ints'', z) <- g mr env ints' (x, y, ints'', z) <- g mr env ints'
return (a <*> x, b . y, ints'', c `mappend` z) return (a <*> x, b . y, ints'', c `mappend` z)
#if MIN_VERSION_transformers(0,6,0)
instance Monad m => Monad (AForm m) where
(AForm f) >>= k = AForm $ \mr env ints -> do
(a, b, ints', c) <- f mr env ints
case a of
FormSuccess r -> do
(x, y, ints'', z) <- unAForm (k r) mr env ints'
return (x, b . y, ints'', c `mappend` z)
FormFailure err -> pure (FormFailure err, b, ints', c)
FormMissing -> pure (FormMissing, b, ints', c)
#endif
instance (Monad m, Monoid a) => Monoid (AForm m a) where instance (Monad m, Monoid a) => Monoid (AForm m a) where
mempty = pure mempty mempty = pure mempty
mappend a b = mappend <$> a <*> b mappend a b = mappend <$> a <*> b