IdrisのEffects
from
Idris
Effectsというpackageを使うことで
Algebraic Effects and Handlers
できるらしい
https://github.com/idris-lang/Idris-dev/tree/master/libs/effects
https://docs.idris-lang.org/en/latest/effects/index.html
https://idris.readthedocs.io/en/v0.9.19/effects/simpleeff.html
https://keens.github.io/slide/effective_idris__effects/