From 47db5d763f4fbfef6540352eb6b84279cc51e26e Mon Sep 17 00:00:00 2001
From: crumbtoo <crumb@disroot.org>
Date: Fri, 5 Jan 2024 10:15:40 -0700
Subject: [PATCH 1/4] KEndo monoid

---
 src/Data/Monoid/Extra.hs | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/Data/Monoid/Extra.hs b/src/Data/Monoid/Extra.hs
index 8f1a763..e3eada4 100644
--- a/src/Data/Monoid/Extra.hs
+++ b/src/Data/Monoid/Extra.hs
@@ -3,10 +3,14 @@
 module Data.Monoid.Extra(
     module Data.Monoid,
     -- * Extra operations
-    mwhen
+    mwhen,
+
+    -- * Kleisli endomorphisms
+    KEndo(KEndo, appKEndo)
     ) where
 
 import Data.Monoid
+import Control.Monad
 
 -- | Like 'Control.Monad.when', but operating on a 'Monoid'. If the first argument
 --   is 'True' returns the second, otherwise returns 'mempty'.
@@ -15,3 +19,16 @@ import Data.Monoid
 -- > mwhen False "test" == ""
 mwhen :: Monoid a => Bool -> a -> a
 mwhen b x = if b then x else mempty
+
+-- | The intersection of 'Data.Monoid.Endo' and 'Control.Arrow.Kleisli'. This
+--   type provides a monoid instance for composition of monadic actions
+--   @a -> m a@.
+newtype KEndo m a = KEndo { appKEndo :: a -> m a }
+
+instance (Monad m) => Semigroup (KEndo m a) where
+    -- | Left-to-right composition
+    KEndo f <> KEndo g = KEndo (f >=> g)
+
+instance (Monad m) => Monoid (KEndo m a) where
+    mempty = KEndo pure
+

From d0c7be5eabed346b47273c3f89afd4da02bc112d Mon Sep 17 00:00:00 2001
From: crumbtoo <crumb@disroot.org>
Date: Mon, 15 Jan 2024 21:55:11 -0700
Subject: [PATCH 2/4] comment

---
 src/Data/Monoid/Extra.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Data/Monoid/Extra.hs b/src/Data/Monoid/Extra.hs
index e3eada4..8f42069 100644
--- a/src/Data/Monoid/Extra.hs
+++ b/src/Data/Monoid/Extra.hs
@@ -21,7 +21,7 @@ mwhen :: Monoid a => Bool -> a -> a
 mwhen b x = if b then x else mempty
 
 -- | The intersection of 'Data.Monoid.Endo' and 'Control.Arrow.Kleisli'. This
---   type provides a monoid instance for composition of monadic actions
+--   type provides a 'Monoid' instance for composition of monadic actions
 --   @a -> m a@.
 newtype KEndo m a = KEndo { appKEndo :: a -> m a }
 

From 772051a6a988a77f0ab06b8a87aae5a5ac992873 Mon Sep 17 00:00:00 2001
From: Sadie Sorceress <lomiskiam@gmail.com>
Date: Wed, 15 May 2024 07:31:59 -0600
Subject: [PATCH 3/4] s/<=</>=>

---
 src/Data/Monoid/Extra.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Data/Monoid/Extra.hs b/src/Data/Monoid/Extra.hs
index 8f42069..5b758e4 100644
--- a/src/Data/Monoid/Extra.hs
+++ b/src/Data/Monoid/Extra.hs
@@ -27,7 +27,7 @@ newtype KEndo m a = KEndo { appKEndo :: a -> m a }
 
 instance (Monad m) => Semigroup (KEndo m a) where
     -- | Left-to-right composition
-    KEndo f <> KEndo g = KEndo (f >=> g)
+    KEndo f <> KEndo g = KEndo (f <=< g)
 
 instance (Monad m) => Monoid (KEndo m a) where
     mempty = KEndo pure

From aa1669a41cf57e5635cbb19d3893a4368d558693 Mon Sep 17 00:00:00 2001
From: Sadie Sorceress <lomiskiam@gmail.com>
Date: Wed, 15 May 2024 07:32:53 -0600
Subject: [PATCH 4/4] comment

---
 src/Data/Monoid/Extra.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Data/Monoid/Extra.hs b/src/Data/Monoid/Extra.hs
index 5b758e4..d04e1b3 100644
--- a/src/Data/Monoid/Extra.hs
+++ b/src/Data/Monoid/Extra.hs
@@ -26,7 +26,7 @@ mwhen b x = if b then x else mempty
 newtype KEndo m a = KEndo { appKEndo :: a -> m a }
 
 instance (Monad m) => Semigroup (KEndo m a) where
-    -- | Left-to-right composition
+    -- | Right-to-left composition
     KEndo f <> KEndo g = KEndo (f <=< g)
 
 instance (Monad m) => Monoid (KEndo m a) where