[Haskell-cafe] Re: Converting IO [XmlTree] to [XmlTree]

Achim Schneider barsoap at web.de
Tue Apr 14 12:29:15 EDT 2009

Cristiano Paris <frodo at theshire.org> wrote:

> I was a bit surprised by the strong reaction about my citation of
> unsafePerformIO. Maybe it'd useful, for the future, to write a
> document explaining how to help newbies properly, maybe putting it in
> the mailing list charter.
1) Tell them about interact.
2) If they're not satisfied, or already spoiled by the functions they
   want to use, explain bind wrt. IO, then do-notation. You don't want
   them to get puzzled by missing returns, or think that it's a keyword.
3) Let them catch up on monads by themselves, there's no need to
   confuse people with explanations of things they already understand.

In other words:

1) Explain Pointed
2) Explain Functor
3) Explain Applicative
4) Explain Monad

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