Blog post: Introducing an effect system

[tristanC]

This blog post explains the reasons we integrated an effect system for the Monocle project.

Introducing an effects system for Monocle

[Kleidukos]

Thanks a lot for publicly writing about it!

[adamse]

Doesn’t ReaderT over IO mean you don’t have the n-squared instances problem?

[Kleidukos]

@adamse Pretty sure you lose all granularity and re-interpretation of effects with ReaderT r IO a

[tristanC]

@adamse, what we observed is that, for example, to use Prometheus or Database.Bloodhound.Client, we had to implement MonadMonitor and MonadBH instances. If I understand correctly, Has* constraints also require an instance for every r. With effectful, we no longer have to create any instance, so that we can use new effects seamlessly.