[Haskell-cafe] Monad classes and FreeT

Nickolay Kudasov nickolay.kudasov at gmail.com
Wed Nov 27 08:55:12 UTC 2013

Hi Alejandro,

That instance (and others) should be in HEAD [1] and will be included in
the next release.

As for considering Free at “the bottom of the stack”, I’m not sure I
understand what you mean. Nonetheless, I think FreeT f m a can be
considered as m actions *delimited* by f actions. Thus Free f a being
simply FreeT f Identity a is just a “sequence” of f actions to be

[1] <https://github.com/ekmett/free>https://github.com/ekmett/free

2013/11/27 Alejandro Serrano Mena <trupill at gmail.com>

> Dear Café,
> I'm continuing my travel through operational and free, and was wondering:
> which is the reason why there's no instance such as
> (Functor f, MonadReader e m) => MonadReader e (FreeT f m)
> included in the 'free' package? It seems reasonable to me to have those
> instances. At least, there's the corresponding one for MonadIO.
> Should Free be considered as some monad to have 'at the bottom of the
> stack' as IO is?
> Thanks in advance.
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20131127/3b7270d8/attachment.html>

More information about the Haskell-Cafe mailing list