[Haskell-cafe] Re: Random obeservations from my playing with Haskell

karczma at info.unicaen.fr karczma at info.unicaen.fr
Sun Dec 5 19:57:24 EST 2004

Scott Turner reacts: 

>> 7. There's a lot of discussion w.r.t state, at least on this list. Is
>> threading state through many functions respectivley polluting many
>> functions with monads the solution?
> If a function is pure, there's never any need to involve it with a monad.  
> Monads don't cause "pollution". They serve to indicate what functions have 
> side effects, while the choice of monad tells what kinds of side effects may 
> occur.  
> Haskell people enjoy pure functions, but are not shy of side effects, which 
> are recognized as an essential feature of every program. Functions that 
> return monadic values provide an excellent way to organize side effects.


Please. DON'T reduce Monads to side effects. This is the domain of the
IO Monad <<et consortes>>, but Monads have many other applications/faces
you most certainly know about. 

Jerzy Karczmarczuk 

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