What do people think about implicit function argument? That is, named function arguments, possibly tagged with something special like a tilde, whereby scoped variables of the same name are automatically passed. The idea is to avoid the pain of a lots of pass through parameters while make it easy to modify one or two of them. For example, in f1 :: ~state::State -> Input -> Output f1 input = f2 input f2 :: ~state::State -> Input -> Output f2 input = <whatever> we don't have to specify ~state for f2 because it picks it up automatically from ~state being in scope from f1. To change it, however, we just do f1 :: ~state::State -> Input -> Output f1 input = f2 input where ~state = <whatever> The advantage over wrapping it in a monad being: 1) it is evident what is being passed around behind the scenes from the type signatures, and 2) we avoiding the lifting issue (to compose multiple implicit arguments we just specifying them -- assuming their are no name clashes). Cheers! -Tyson