One function missing in Data.Map
Isn't the function adjustLookupWithKey missing in Data.Map? There are functions ending in LookupWithKey for both insert and update but not for adjust.
adjustLookupWithKey :: Ord k => (k -> a -> Maybe a) -> k -> Map k a -> (Maybe a, Map k a)
adjustLookupWithKey f k m[[BR]]
==> (Nothing, m) if k is not in m[[BR]] ==> (Just old, m) if f x is Nothing[[BR]] ==> (Just new, m') if f x is Just new, and m' being m adjusted
The same behavior could be simulated using library function and user defined function, but I it deserves an implementation.
Trac metadata
Trac field | Value |
---|---|
Version | 6.12.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | libraries (other) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |