I am trying to write an interpreter for a very simple untyped functional
language. I have a problem with mutually recursive let expressions, for
which my interpreter loops :(
This is a code snippet from the eval function:
eval :: Expr - Eval Value
eval (Let decls body) = mdo
let
The following code works fine for me, so it seems you are missing some
details that may help.
{-# LANGUAGE RecursiveDo, GeneralizedNewtypeDeriving,
TypeSynonymInstances, MultiParamTypeClasses #-}
import Control.Monad
import Control.Monad.State
import Control.Monad.Error
import
