Koka[1] jumps to mind as a language built around effect types. Without having used Flex or Koka, I'm not sure how their effect types actually differ from the no

Koka[1] jumps to mind as a language built around effect types. Without having used Flex or Koka, I'm not sure how their effect types actually differ from the normal monad gauntlet you get in pure languages. [1] - https://koka-lang.github.io/koka/doc/index.html https://koka-lang.github.io/koka/doc/index.html