From 778689dcf679cdb00fcd1ad0ee1f4492d7e8a164 Mon Sep 17 00:00:00 2001
From: ocramz <zocca.marco@gmail.com>
Date: Tue, 15 Jan 2019 12:20:56 +0100
Subject: [PATCH 1/3] add Array.foldlM' and foldlWithKeyM'

---
 Data/HashMap/Array.hs       | 13 +++++++++++++
 Data/HashMap/Base.hs        | 12 ++++++++++++
 Data/HashMap/Lazy.hs        |  1 +
 Data/HashMap/Strict.hs      |  1 +
 Data/HashMap/Strict/Base.hs |  1 +
 5 files changed, 28 insertions(+)

diff --git a/Data/HashMap/Array.hs b/Data/HashMap/Array.hs
index 0149da4d..f60ae15d 100644
--- a/Data/HashMap/Array.hs
+++ b/Data/HashMap/Array.hs
@@ -43,6 +43,7 @@ module Data.HashMap.Array
       -- * Folds
     , foldl'
     , foldr
+    , foldlM'
 
     , thaw
     , map
@@ -418,6 +419,18 @@ foldl' f = \ z0 ary0 -> go ary0 (length ary0) 0 z0
             (# x #) -> go ary n (i+1) (f z x)
 {-# INLINE foldl' #-}
 
+foldlM' :: Monad m => (b -> a -> m b) -> b -> Array a -> m b
+foldlM' f = \ z0 ary0 -> go ary0 (length ary0) 0 z0
+  where
+    go ary n i !z
+        | i >= n = pure z
+        | otherwise
+        = case index# ary i of
+            (# x #) -> do
+              fzx <- f z x
+              go ary n (i+1) fzx
+{-# INLINE foldlM' #-}              
+
 foldr :: (a -> b -> b) -> b -> Array a -> b
 foldr f = \ z0 ary0 -> go ary0 (length ary0) 0 z0
   where
diff --git a/Data/HashMap/Base.hs b/Data/HashMap/Base.hs
index 553d2b3a..019c84e8 100644
--- a/Data/HashMap/Base.hs
+++ b/Data/HashMap/Base.hs
@@ -58,6 +58,7 @@ module Data.HashMap.Base
       -- * Folds
     , foldl'
     , foldlWithKey'
+    , foldlWithKeyM'
     , foldr
     , foldrWithKey
 
@@ -1551,6 +1552,17 @@ foldlWithKey' f = go
     go z (Collision _ ary)     = A.foldl' (\ z' (L k v) -> f z' k v) z ary
 {-# INLINE foldlWithKey' #-}
 
+-- | /O(n)/ Monadic version of 'foldlWithKey''.
+foldlWithKeyM' :: Monad m => (a -> k -> v -> m a) -> a -> HashMap k v -> m a
+foldlWithKeyM' f = go
+  where
+    go !z Empty                = pure z
+    go z (Leaf _ (L k v))      = f z k v
+    go z (BitmapIndexed _ ary) = A.foldlM' go z ary
+    go z (Full ary)            = A.foldlM' go z ary
+    go z (Collision _ ary)     = A.foldlM' (\ z' (L k v) -> f z' k v) z ary
+{-# INLINE foldlWithKeyM' #-}    
+
 -- | /O(n)/ Reduce this map by applying a binary operator to all
 -- elements, using the given starting value (typically the
 -- right-identity of the operator).
diff --git a/Data/HashMap/Lazy.hs b/Data/HashMap/Lazy.hs
index c7306350..7362c8a8 100644
--- a/Data/HashMap/Lazy.hs
+++ b/Data/HashMap/Lazy.hs
@@ -70,6 +70,7 @@ module Data.HashMap.Lazy
       -- * Folds
     , foldl'
     , foldlWithKey'
+    , foldlWithKeyM'
     , foldr
     , foldrWithKey
 
diff --git a/Data/HashMap/Strict.hs b/Data/HashMap/Strict.hs
index 3af68b7f..1bf87929 100644
--- a/Data/HashMap/Strict.hs
+++ b/Data/HashMap/Strict.hs
@@ -69,6 +69,7 @@ module Data.HashMap.Strict
       -- * Folds
     , foldl'
     , foldlWithKey'
+    , foldlWithKeyM'
     , foldr
     , foldrWithKey
 
diff --git a/Data/HashMap/Strict/Base.hs b/Data/HashMap/Strict/Base.hs
index 890d18ff..cc8122e6 100644
--- a/Data/HashMap/Strict/Base.hs
+++ b/Data/HashMap/Strict/Base.hs
@@ -71,6 +71,7 @@ module Data.HashMap.Strict.Base
       -- * Folds
     , foldl'
     , foldlWithKey'
+    , foldlWithKeyM' 
     , HM.foldr
     , foldrWithKey
 

From 039a443b4e794174967fdccf1cc9a65e7b83484e Mon Sep 17 00:00:00 2001
From: ocramz <zocca.marco@gmail.com>
Date: Tue, 15 Jan 2019 12:42:11 +0100
Subject: [PATCH 2/3] fix for backwards compat

---
 Data/HashMap/Array.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Data/HashMap/Array.hs b/Data/HashMap/Array.hs
index f60ae15d..ccdcf9dd 100644
--- a/Data/HashMap/Array.hs
+++ b/Data/HashMap/Array.hs
@@ -423,7 +423,7 @@ foldlM' :: Monad m => (b -> a -> m b) -> b -> Array a -> m b
 foldlM' f = \ z0 ary0 -> go ary0 (length ary0) 0 z0
   where
     go ary n i !z
-        | i >= n = pure z
+        | i >= n = return z
         | otherwise
         = case index# ary i of
             (# x #) -> do

From 9febf1b35ac4d01479c2922f9db63f88d41c3f12 Mon Sep 17 00:00:00 2001
From: ocramz <zocca.marco@gmail.com>
Date: Tue, 15 Jan 2019 12:49:54 +0100
Subject: [PATCH 3/3] fix for backwards compat

---
 Data/HashMap/Base.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Data/HashMap/Base.hs b/Data/HashMap/Base.hs
index 019c84e8..d6b28f54 100644
--- a/Data/HashMap/Base.hs
+++ b/Data/HashMap/Base.hs
@@ -1556,7 +1556,7 @@ foldlWithKey' f = go
 foldlWithKeyM' :: Monad m => (a -> k -> v -> m a) -> a -> HashMap k v -> m a
 foldlWithKeyM' f = go
   where
-    go !z Empty                = pure z
+    go !z Empty                = return z
     go z (Leaf _ (L k v))      = f z k v
     go z (BitmapIndexed _ ary) = A.foldlM' go z ary
     go z (Full ary)            = A.foldlM' go z ary