From 55a24136798a2998fdf64353bc0b0fa95a9db22e Mon Sep 17 00:00:00 2001
From: William Rusnack <rusnackw@umich.edu>
Date: Tue, 14 Jul 2020 07:10:02 -0400
Subject: [PATCH 1/4] overPost

---
 src/Data/Lens/Setter.purs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/Data/Lens/Setter.purs b/src/Data/Lens/Setter.purs
index 8434e9e..07bb94b 100644
--- a/src/Data/Lens/Setter.purs
+++ b/src/Data/Lens/Setter.purs
@@ -34,6 +34,7 @@ import Data.Maybe (Maybe(..))
 import Data.Tuple (uncurry)
 
 infixr 4 over as %~
+infixr 4 overPost as <%~ 
 infixr 4 set as .~
 infixr 4 addOver as +~
 infixr 4 subOver as -~
@@ -47,6 +48,7 @@ infixr 4 setJust as ?~
 
 infix 4 assign as .=
 infix 4 modifying as %=
+infix 4 modifyingLensPost as <%=
 infix 4 addModifying as +=
 infix 4 mulModifying as *=
 infix 4 subModifying as -=
@@ -103,6 +105,18 @@ assign p b = void (modify (set p b))
 modifying :: forall s a b m. MonadState s m => Setter s s a b -> (a -> b) -> m Unit
 modifying p f = void (modify (over p f))
 
+overPost :: forall s t a b. Lens s t a b -> (a -> b) -> s -> Tuple b t
+overPost l f x = Tuple y (x # l .~ y)
+  where
+    y = x ^. l <<< to f
+
+modifyingLensPost :: forall s a m. MonadState s m => Lens' s a -> (a -> a) -> m a
+modifyingLensPost l f = do
+  s <- get
+  let Tuple x s' = s # l <%~ f
+  put s'
+  pure x
+
 addModifying :: forall s a m. MonadState s m => Semiring a => Setter' s a -> a -> m Unit
 addModifying p = modifying p <<< add
 

From df703867ce46a214cf5ca7fa82e18dbe85dab39c Mon Sep 17 00:00:00 2001
From: William Rusnack <rusnackw@umich.edu>
Date: Tue, 14 Jul 2020 07:22:02 -0400
Subject: [PATCH 2/4] reordered

---
 src/Data/Lens/Setter.purs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Data/Lens/Setter.purs b/src/Data/Lens/Setter.purs
index 07bb94b..7feb089 100644
--- a/src/Data/Lens/Setter.purs
+++ b/src/Data/Lens/Setter.purs
@@ -63,6 +63,11 @@ infix 4 assignJust as ?=
 over :: forall s t a b. Setter s t a b -> (a -> b) -> s -> t
 over l = l
 
+overPost :: forall s t a b. Lens s t a b -> (a -> b) -> s -> Tuple b t
+overPost l f x = Tuple y (x # l .~ y)
+  where
+    y = x ^. l <<< to f
+
 -- | Apply a function to the foci of a `Setter` that may vary with the index.
 iover :: forall i s t a b. IndexedSetter i s t a b -> (i -> a -> b) -> s -> t
 iover l f = l (Indexed $ uncurry f)
@@ -105,11 +110,6 @@ assign p b = void (modify (set p b))
 modifying :: forall s a b m. MonadState s m => Setter s s a b -> (a -> b) -> m Unit
 modifying p f = void (modify (over p f))
 
-overPost :: forall s t a b. Lens s t a b -> (a -> b) -> s -> Tuple b t
-overPost l f x = Tuple y (x # l .~ y)
-  where
-    y = x ^. l <<< to f
-
 modifyingLensPost :: forall s a m. MonadState s m => Lens' s a -> (a -> a) -> m a
 modifyingLensPost l f = do
   s <- get

From ef0b86e89a8a9788f0a4aff00d9a7512a751ca3f Mon Sep 17 00:00:00 2001
From: William Rusnack <rusnackw@umich.edu>
Date: Tue, 14 Jul 2020 07:41:22 -0400
Subject: [PATCH 3/4] imports

---
 src/Data/Lens/Setter.purs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/Data/Lens/Setter.purs b/src/Data/Lens/Setter.purs
index 7feb089..f9b9e58 100644
--- a/src/Data/Lens/Setter.purs
+++ b/src/Data/Lens/Setter.purs
@@ -27,11 +27,12 @@ module Data.Lens.Setter
 
 import Prelude
 
-import Control.Monad.State.Class (class MonadState, modify)
+import Control.Monad.State.Class (class MonadState, modify, get, put)
 
-import Data.Lens.Types (IndexedSetter, Indexed(..), Setter, Setter')
+import Data.Lens.Getter ((^.), to)
+import Data.Lens.Types (IndexedSetter, Indexed(..), Setter, Setter', Lens, Lens')
 import Data.Maybe (Maybe(..))
-import Data.Tuple (uncurry)
+import Data.Tuple (Tuple(Tuple), uncurry)
 
 infixr 4 over as %~
 infixr 4 overPost as <%~ 

From 2819e0b4e592f845cadea615e7fcf2dd3c989364 Mon Sep 17 00:00:00 2001
From: William Rusnack <rusnackw@umich.edu>
Date: Tue, 14 Jul 2020 07:53:06 -0400
Subject: [PATCH 4/4] export

---
 src/Data/Lens/Setter.purs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Data/Lens/Setter.purs b/src/Data/Lens/Setter.purs
index f9b9e58..c5f8f76 100644
--- a/src/Data/Lens/Setter.purs
+++ b/src/Data/Lens/Setter.purs
@@ -1,6 +1,7 @@
 -- | This module defines functions for working with setters.
 module Data.Lens.Setter
   ( (%~),  over, iover
+  , (<%~), overPost
   , (.~),  set
   , (+~),  addOver
   , (-~),  subOver
@@ -13,6 +14,7 @@ module Data.Lens.Setter
   , (?~),  setJust
   , (.=),  assign
   , (%=),  modifying
+  , (<%=), modifyingLensPost
   , (+=),  addModifying
   , (*=),  mulModifying
   , (-=),  subModifying