[pooya72]

Wouldn't this be something similiar to Monads? I remember someone gave a talk and described Monads as "worlds". (I forgot which video it was). So a function goes into a "world" does all it's stuff, then it exits and comes down.

[tsimionescu]

The "Monads=worlds" comparison sounds appealing for some monads (IO, ST), but is extremely unintuitive for others (List).