I've just locked an open door. Strange, yet symbolically compelling.
Manny Calavera, Grim Fandango
Have you ever wanted to manage siiiick invariants with indexed monads without
giving up your regular monads in the process? do-notation lets you do this
with a bunch of type jiggery-pokery behind the scenes.
It also provides the Ix m indexed monad which is a free construction over a
regular monad m. Cool.
{-# LANGUAGE RebindableSyntax #-}
import Language.Haskell.DoNotation
import Prelude hiding (Monad (..), pure)The implementation doesn't play very nicely with do-blocks bound via let.
Huge shout-outs to Csongor Kiss for very patiently walking me through the incoherent instance machinery necessary to make this all work.