Replace tuples with strict datatype

This commit changes the recursive helpers in functions that modify
a hashmap's size to return a 'Sized' value (with strict fields)
instead of the base tuples.

Author: rockbmb

Data/HashMap/Array.hs

@@ -10,6 +10,7 @@ module Data.HashMap.Array
     , RunRes (..)
     , RunResA
     , RunResM
+    , Sized (..)
 
       -- * Creation
     , new
@@ -316,12 +317,17 @@ updateWith' :: Array e -> Int -> (e -> e) -> Array e
 updateWith' ary idx f = update ary idx $! f (index ary idx)
 {-# INLINE updateWith' #-}
 
+-- | Helper datatype used in 'updateWithInternal''. Used when a change in
+-- a value's size must be returned along with the value itself (typically
+-- a hashmap).
+data Sized a = Sized {-# UNPACK #-} !Int !a
+
 -- | /O(n)/ Update the element at the given positio in this array, by
 -- applying a function to it.  Evaluates the element to WHNF before
 -- inserting it into the array.
-updateWithInternal' :: Array e -> Int -> (e -> (Int, e)) -> RunResA e
+updateWithInternal' :: Array e -> Int -> (e -> Sized e) -> RunResA e
 updateWithInternal' ary idx f =
-    let !(!sz, !e) = f (index ary idx)
+    let Sized sz e = f (index ary idx)
     in RunRes sz (update ary idx e)
 {-# INLINE updateWithInternal' #-}