0.12.0 release, the
Effect monad used to be called
In short, the decision was made to drop
Eff's "extensible effects". Presumably, to prevent code breakage,
Eff and package location in imports was unchanged. Rather, it can now be found in the purescript-eff package. Its replacement was called
Aff monad was introduced and in use before this decision was made. Thus, history explains the naming behind
Eff was for synchronous effects, then
Aff is for asychronous effects.
Aff will be covered in more depth in the upcoming files.