Clinton
Reputation: 23135
Is there a class with the function `(m a -> n b) -> t m a -> t n b`
Here's a class, I'm calling BlahMap:
class BlahMap t where
blahMap :: (m a -> n b) -> t m a -> t n b
This is an instance of BlahMap:
instance BlahMap (ReaderT r) where
blahMap f = ReaderT . fmap f . runReaderT
Is there an existing class in the Haskell ecosystem that does this? Or alternatively, can I just write a function blahMap with appropriate constraints with existing classes in say mtl or something similar? Or have I actually invented something new?
Upvotes: 6
Views: 112
Answers (1)
Related Questions
- How do define a monad transformer that is the composition of two arbitrary monad transformers?
- Haskell - is there extended monad type [ m (a -> m b) -> m a -> m b ]
- Is it possible to write a function of the type `Monad m => t Identity a -> t m a` for every monad transformer `t`?
- Has anyone ever encountered a Monad Transformer in the wild?
- Examples of Haskell Applicative Transformers
- Applicative transformer classes
- Is there a `m a -> (a -> m b) -> m a` function type in haskell?
- Is there a library or typeclass for getting the transformer version of a monad?
- What's the best way to support monad transformers, in functions that take monadic commands as arguments?
- mapMonadTrans :: MonadTrans xT => (m a -> n b) -> xT m a -> xT n b