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

Cristiano Paris frodo at theshire.org
Tue Apr 14 11:24:40 EDT 2009

On Tue, Apr 14, 2009 at 5:09 PM, Luke Palmer <lrpalmer at gmail.com> wrote:
> ...
> Please don't say that.  He's a beginner.
> You realize that the path of least resistance will be to use it, right?
> You see why that's not a good thing?
> Even experts don't use this function.
> (To the O.P.:  don't use it)

Mmmh, sorry Luke but I don't understand this ostracism.

unsafePerformIO is not "evil" by itself, it's there for a purpose and,
as for anything else in the language, it's better to understand when
to use it and when not rather than just knowing that is something that
MUST not be used, without any further explanation.

More, from my personal experience, knowing unsafePerformIO helped me
understand better what Monads are and how they should be used.

I wounder what so-called "experts" have to say about this.


More information about the Haskell-Cafe mailing list