[tome]

> This shouldn't even be proposed as a question to someone new to Haskell. They should learn how monad transformers work and just use them. 90% of developers playing around effect systems would be just fine with MTL or even just concrete transformers. All Haskell effect systems should be considered experimental at this point with unclear shelf lives.

This is highly debatable. I would say that the effect systems effectful and Bluefin are actually significantly simpler than MTL and transformers, particularly as soon as you need to do prompt resource cleanup.

Personally I'd say that if newbies should start with naked IO and then switch to effectful or Bluefin once they've realised the downside of IO being available everywhere.

> All Haskell effect systems should be considered experimental at this point with unclear shelf lives.

effectful and Bluefin are here to stay. I guarantee it. For non-IO-based effect systems (e.g. polysemy, freer-effects) I agree.

(Disclaimer: I'm the author of Bluefin)

[solomonb]

> effectful and Bluefin are here to stay. I guarantee it. For non-IO-based effect systems (e.g. polysemy, freer-effects) I agree.

Just to be clear I think Bluefin is really cool and I'm a fan of your work overall.

I'm speaking from the industry/production perspective here. When polysemy and freer-effects were released there was a similar belief that they were here to stay.

transformers and MTL have stood the test of time, are heavily documented, and are pervasive throughout Hackage. Understanding them and how to build programs with them is essential for anyone trying to break into 'production haskell' as a career move.

[tome]

> Just to be clear I think Bluefin is really cool and I'm a fan of your work overall.

Thanks!

> I'm speaking from the industry/production perspective here. When polysemy and freer-effects were released there was a similar belief that they were here to stay.

Well, from my perspective, I've never worked at a place that's used polysemy of freer-effects.

> transformers and MTL have stood the test of time, are heavily documented, and are pervasive throughout Hackage. Understanding them and how to build programs with them is essential for anyone trying to break into 'production haskell' as a career move.

Sadly true.

[solomonb]

> Well, from my perspective, I've never worked at a place that's used polysemy of freer-effects.

I have with another deprecated effect library. Its a bummer to have something so core to the architecture that is deprecated but then to not have the time or buy-in to do anything about it.

[tome]

That does sound like a bummer. To add some explanation, to explain why I said that effectful and Bluefin are here to say, it's because they're based on IO, so it's easy to get them to interoperate, and if in the future a new "EffectSystemX" comes along, also based on IO, then they will interoperate with that too. Thus the risk of them being deprecated is minimal.

I haven't published my effectful-Bluefin interoperation layer, but you can see it here:

https://github.com/tomjaguarpaw/bluefin/blob/caa59700d910c76...