The Better platform gets around half a million learning actions every week and it has been running for well over a year with no downtime or maintenance. We still don’t know of any bugs.
What I’ve found when working with Haskell relative to Ruby is I have a much higher level of confidence in the system even without writing any tests.
This library provides first-class multi-arity product- and sum-types and neat type-level utilities for their composition.
ghc-mod is both a back-end program for enhancing editors and other development environments with support for Haskell as well as a library for abstracting the black magic incantations required to use the GHC API in various environments
SML is really limited to the areas of the Haskell type system you’d be accustomed to after reading Learn You A Haskell!
The compiler only states what doesn’t work, this is about what does work.