On 15/10/16 15:49, Joachim Breitner wrote:
Hi,
Am Freitag, den 14.10.2016, 17:35 +0200 schrieb Damian Nadales:
Do you have any experience using any of these approaches. If so would you mind sharing? ;)
I don’t have an answer to contribute, but I would be very interested in hearing about experiences in terms of their relative runtime performance.
My gut feeling is that an an indirect function call for every (>>=), with many calls to `lift` each time, would make a deep monad transformer stack much more expensive. A free monad approach seems to be more sensible to me. But maybe GHC is doing a better job optimizing this than I would think?
So if you have any number-supported evidence about this, possibly from a real-world application where you tried to use one or the other, please share it with us!
There's a paper from Oleg discussing "Freer Monads, More Extensible Effects": http://okmij.org/ftp/Haskell/extensible/more.pdf The conclusion there seems to be that the EE approach is more "efficient". But you'll have to look at the concrete performance cases and data yourself to make a judgement.