Add HashMap.findWithDefault.

This function is equivalent to `lookupDefault` but uses the same name that
the containers package
uses (https://hackage.haskell.org/package/containers-0.5.10.2/docs/Data-Map-Strict.html#v:findWithDefault).

This partially addresses #172.

Data/HashMap/Base.hs

@@ -19,6 +19,7 @@ module Data.HashMap.Base
     , size
     , member
     , lookup
+    , findWithDefault
     , lookupDefault
     , (!)
     , insert
@@ -450,12 +451,24 @@ lookup k0 m0 = go h0 k0 0 m0
 
 -- | /O(log n)/ Return the value to which the specified key is mapped,
 -- or the default value if this map contains no mapping for the key.
-lookupDefault :: (Eq k, Hashable k)
+--
+-- @since 0.2.9
+findWithDefault :: (Eq k, Hashable k)
               => v          -- ^ Default value to return.
               -> k -> HashMap k v -> v
-lookupDefault def k t = case lookup k t of
+findWithDefault def k t = case lookup k t of
     Just v -> v
     _      -> def
+{-# INLINABLE findWithDefault #-}
+
+
+-- | /O(log n)/ Return the value to which the specified key is mapped,
+-- or the default value if this map contains no mapping for the key.
+{-# DEPRECATED lookupDefault "As of version 0.2.9, replaced by 'findWithDefault'." #-}
+lookupDefault :: (Eq k, Hashable k)
+              => v          -- ^ Default value to return.
+              -> k -> HashMap k v -> v
+lookupDefault def k t = findWithDefault def k t
 {-# INLINABLE lookupDefault #-}
 
 -- | /O(log n)/ Return the value to which the specified key is mapped.

Data/HashMap/Lazy.hs

@@ -38,6 +38,7 @@ module Data.HashMap.Lazy
     , size
     , member
     , HM.lookup
+    , findWithDefault
     , lookupDefault
     , (!)
     , insert

Data/HashMap/Strict.hs

@@ -38,6 +38,7 @@ module Data.HashMap.Strict
     , size
     , HM.member
     , HM.lookup
+    , findWithDefault
     , lookupDefault
     , (!)
     , insert

tests/Strictness.hs

@@ -55,6 +55,9 @@ pSingletonValueStrict k = isBottom $ (HM.singleton k (bottom :: Int))
 pLookupDefaultKeyStrict :: Int -> HashMap Key Int -> Bool
 pLookupDefaultKeyStrict def m = isBottom $ HM.lookupDefault def bottom m
 
+pFindWithDefaultKeyStrict :: Int -> HashMap Key Int -> Bool
+pFindWithDefaultKeyStrict def m = isBottom $ HM.findWithDefault def bottom m
+
 pAdjustKeyStrict :: (Int -> Int) -> HashMap Key Int -> Bool
 pAdjustKeyStrict f m = isBottom $ HM.adjust f bottom m
 
@@ -161,6 +164,7 @@ tests =
       , testProperty "member is key-strict" $ keyStrict HM.member
       , testProperty "lookup is key-strict" $ keyStrict HM.lookup
       , testProperty "lookupDefault is key-strict" pLookupDefaultKeyStrict
+      , testProperty "findWithDefault is key-strict" pFindWithDefaultKeyStrict
       , testProperty "! is key-strict" $ keyStrict (flip (HM.!))
       , testProperty "delete is key-strict" $ keyStrict HM.delete
       , testProperty "adjust is key-strict" pAdjustKeyStrict