Re: Is join useful for every monad?

Welp. So IO (IO a) is a thing. Will I ever encounter ReadPrec (ReadPrec a)? 2019년 10월 14일 (월) 14:42, Dmitrii Kovanikov 님이 작성:

Data types like `IO (IO a)` are useful and their usage is described in the following blog post:

* http://www.haskellforall.com/2018/02/the-wizard-monoid.html

One function from the example uses `join` directly:

runWizard :: IO (IO a) -> IO a runWizard = join

On Mon, Oct 14, 2019 at 7:55 AM Dannyu NDos wrote:

...

join is surely useful for Maybe and [].

But IO (IO a)? ReadPrec (ReadPrec a)? ST s (ST s a)? When the heck could I encounter such types? _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries