[Haskell-cafe] Explaining monads

Alex Queiroz asandroq at gmail.com
Tue Aug 14 12:46:15 EDT 2007


On 8/14/07, Jeff Polakow <jeff.polakow at db.com> wrote:
> Hello,
> There is clearly a problem with the Haskell/monad tutorials out there...
> > The tutorials seriously need to step back and start with
>  > something like, "To enforce order of evaluation we evaluate
>  > closures* returning a defined type.  The first closure will feed
>  > its result to the second which will in turn feed it's result to
>  > the third.  Since the third closure can't be evaluated without
>  > having the results from the second and first (and thus they had
>  > to be evaluated earlier in time) we get a defined evaluation
>  > sequence.  Here are some examples..."
>  >
> The style of this description is nice; however the description itself is
> wrong.
> Monads DO NOT determine order of evaluation. Previous posts on this thread
> give several examples.

     And his point was completely missed.


More information about the Haskell-Cafe mailing list