letrec + typechecking core

2024-02-08 18:40:46 -07:00
parent a2b4bd2afc
commit 17058d3f8c
6 changed files with 47 additions and 24 deletions
--- a/src/Control/Monad/Errorful.hs
+++ b/src/Control/Monad/Errorful.hs
@@ -8,6 +8,7 @@ module Control.Monad.Errorful
    , errorful
    , runErrorful
    , mapErrorful
+    , hoistErrorfulT
    , MonadErrorful(..)
    )
    where
@@ -74,6 +75,9 @@ mapErrorful f (ErrorfulT m) = ErrorfulT $
 --    mapErrorful f = coerced . mapped . _2 . mapped %~ f
 -- lol

+hoistErrorfulT :: (forall a. m a -> n a) -> ErrorfulT e m a -> ErrorfulT e n a
+hoistErrorfulT nt (ErrorfulT m) = ErrorfulT (nt m)
+
 --------------------------------------------------------------------------------
 -- daily dose of n^2 instances