New subject: I have a -> f a. How to get m a -> f m a ?

4 Sep 2017

      Hello List!

I have function a -> IO a. How to get function:

  Maybe a -> IO (Maybe a)  ?

I found in Haskell mails archive such thing:

   class IFunctor f where
     imap :: Idiom i => (s -> i t) -> f s -> i (f t)

which looks similar, but I didn't find any helpfull instances of
`IFunctor` class in its package (and unfortunately I don't know what are
the indexed types: IMonad, IFunctor, etc). Sure, there is the primitive
solution like:

   myfunc :: a -> IO a
   ...
   f x = case x of Nothing -> return Nothing
                   Just x' -> Just <$> myfunc x'

but more interesting is to know more standard and Haskelish solution
(like lift's, etc). May be I miss something very obvious..

===
Best regards, Paul

I have a -> f a. How to get m a -> f m a ?

Baa

Imants Cekusins

Baa

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