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1. mapMaybeMissing :: forall (f :: Type -> Type) x y . Applicative f => (Key -> x -> Maybe y) -> WhenMissing f x y

   ghc-lib-parser	GHC.Data.Word64Map.Internal

   Map over the entries whose keys are missing from the other map, optionally removing some. This is the most powerful SimpleWhenMissing tactic, but others are usually more efficient.

   mapMaybeMissing :: (Key -> x -> Maybe y) -> SimpleWhenMissing x y
   

   mapMaybeMissing f = traverseMaybeMissing (\k x -> pure (f k x))
   

   but mapMaybeMissing uses fewer unnecessary Applicative operations.

2. mapMaybeWithKey :: (Key -> a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Internal

   Map keys/values and collect the Just results.

   let f k _ = if k < 5 then Just ("key : " ++ (show k)) else Nothing
   mapMaybeWithKey f (fromList [(5,"a"), (3,"b")]) == singleton 3 "key : 3"
   

3. mapMissing :: forall (f :: Type -> Type) x y . Applicative f => (Key -> x -> y) -> WhenMissing f x y

   ghc-lib-parser	GHC.Data.Word64Map.Internal

   Map over the entries whose keys are missing from the other map.

   mapMissing :: (k -> x -> y) -> SimpleWhenMissing x y
   

   mapMissing f = mapMaybeMissing (\k x -> Just $ f k x)
   

   but mapMissing is somewhat faster.

4. mapMaybe :: (a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Lazy

   Map values and collect the Just results.

   let f x = if x == "a" then Just "new a" else Nothing
   mapMaybe f (fromList [(5,"a"), (3,"b")]) == singleton 5 "new a"
   

5. mapMaybeWithKey :: (Key -> a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Lazy

   Map keys/values and collect the Just results.

   let f k _ = if k < 5 then Just ("key : " ++ (show k)) else Nothing
   mapMaybeWithKey f (fromList [(5,"a"), (3,"b")]) == singleton 3 "key : 3"
   

6. mapMaybe :: (a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Strict

   Map values and collect the Just results.

   let f x = if x == "a" then Just "new a" else Nothing
   mapMaybe f (fromList [(5,"a"), (3,"b")]) == singleton 5 "new a"
   

7. mapMaybeWithKey :: (Key -> a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Strict

   Map keys/values and collect the Just results.

   let f k _ = if k < 5 then Just ("key : " ++ (show k)) else Nothing
   mapMaybeWithKey f (fromList [(5,"a"), (3,"b")]) == singleton 3 "key : 3"
   

8. mapMaybe :: (a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Strict.Internal

   Map values and collect the Just results.

   let f x = if x == "a" then Just "new a" else Nothing
   mapMaybe f (fromList [(5,"a"), (3,"b")]) == singleton 5 "new a"
   

9. mapMaybeWithKey :: (Key -> a -> Maybe b) -> Word64Map a -> Word64Map b

   ghc-lib-parser	GHC.Data.Word64Map.Strict.Internal

   Map keys/values and collect the Just results.

   let f k _ = if k < 5 then Just ("key : " ++ (show k)) else Nothing
   mapMaybeWithKey f (fromList [(5,"a"), (3,"b")]) == singleton 3 "key : 3"
   

10. mapMonotonic :: (Key -> Key) -> Word64Set -> Word64Set

    ghc-lib-parser	GHC.Data.Word64Set

    The mapMonotonic f s == map f s, but works only when f is strictly increasing. The precondition is not checked. Semi-formally, we have:

    and [x < y ==> f x < f y | x <- ls, y <- ls]
    ==> mapMonotonic f s == map f s
    where ls = toList s
    

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