[Haskell-beginners] Re: Are monads pure?
apfelmus at quantentunnel.de
Tue May 18 05:30:33 EDT 2010
Andres Loeh wrote:
> Nevertheless, people often refer to features such as state
> and exceptions as "effects", and hence sometimes call code that makes
> use of them "effectful" and code that does not "pure".
This makes sense if you think of monads as embedded domain specific
languages. In the jargon of, say the DSL corresponding to the state
monad, the operation put has an "effect". But the embedding into
Haskell maps put to a pure function of type s -> ((),s) .
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