`eff` is a research project that is no longer in active development and never made it to production in any sense. It would be AMAZING if `eff` were completed but I dont think that will happen at this point.

`eff` is based on delimited continuations (which Alexis had to build into GHC), it is not using `Freer`. If you want to look at an effect system in Haskell that actually has been used in production AND is based on this paper then look at `freer-simple`: https://hackage.haskell.org/package/freer-simple

No it is not high performance, but neither are any other Haskell effect systems and performance is relative to your problem domain. It also has the benefit of being implemented very similarly to Oleg's paper making it a lot easier to learn from then most other options.

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tome 4 hours ago | parent [-]

> No it is not high performance, but neither are any other Haskell effect systems

This is not true. IO-wrapper effect systems (in practice, effectful or Bluefin) have as good performance as Haskell's IO monad, that is to say as good as you can get in Haskell.

	▲	solomonb 3 hours ago \| parent [-]
		Yes but from what I understand at a loss of safety. You can decide if that is worth it but you aren't getting a free lunch. that said, your library is really cool. : )