ppetr

Result size = 325

Main.$fFunctorTreeT_$cfmap
  :: forall a_ajJ b_ajK.
     (a_ajJ -> b_ajK) -> Main.TreeT a_ajJ -> Main.TreeT b_ajK
[GblId,
 Arity=2,
 Caf=NoCafRefs,
 Str=DmdType LS,
 Unf=Unf{Src=<vanilla>, TopLvl=True, Arity=2, Value=True,

ppetr

module CoerceUsingUnsafe where

import Data.IORef
import System.IO.Unsafe (unsafePerformIO)

import Data.Word

{- The trick behind this function is in the `test` experession.
   When we create a new mutable variable in the IO monad,
   it has a side effect of creating it somewhere in the memory.

ppetr

http://stackoverflow.com/q/10236953/1333025

I quite enjoyed this exercise. I tried to do it without looking at the answers,
and it was worth it. It took me considerable time, but the result is
surprisingly close to two of the other answers, as well as to
[monad-coroutine](http://hackage.haskell.org/package/monad-coroutine) library.
So I guess this is somewhat natural solution to this problem. Without this
exercise, I wouldn't understand how _monad-coroutine_ really works.

To add some additional value, I'll explain the steps that eventually led me to