Sat Sep 5 15:30:37 CEST 2015

Two-object state?

Erlang's imperative part basically is message passing.  I've noticed
this pattern: A two-process combo where one implements the control
flow, and the other implements memory access through RPC.

What other side effects can be implemented that way?

EDIT: Really?  "Our alternative to a monad transformer stack is the
single monad, for the coroutine-like communication of a client with
its handler." [1]

So this is the Eff Monad.  I did run into that name before but don't
recall the concept.  Maybe it was the Eff language base on algebraic
effects[2].  And also PureScript[3].

[1] http://okmij.org/ftp/Haskell/extensible/index.html#introduction
[2] http://www.eff-lang.org/
[3] http://www.purescript.org/learn/eff/