Add typelevel salt #1
Open
+437
−229
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
jappeace
force-pushed
the
add-typelevel-salt
branch
4 times, most recently
from
7a4681c to
73fa02e
Compare
This allows clients to create custom salted hashmaps.
For backwards compatibility we use
```haskell
-- backwards compatibility
type HashMap = HashMapT DefaultSalt
```
Then modify the functions to be free of salt if they can, for example insert:
```haskell
insert :: forall k v salt . (Eq k, Hashable k) => k -> v -> HashMapT salt k v -> HashMapT salt k v
insert k v m = insert' (hash salt k) k v m
where
salt = natVal (Proxy :: Proxy salt)
```
This allows the default HashMap with backwards compatibility,
but also any other HashMapT
I think this solves the issue with having different salts in
an intersect:
```haskell
intersection :: (Eq k, Hashable k) => HashMapT salt k v -> HashMapT salt k w -> HashMapT salt k v
```
Because salt is the same type variable for all arguments,
it's enforced to be the same.
Then you can also provide a function to resalt if the user ever ends
up with different salts and still wants to do an intersect.
(which results in a reconstruction of the hashmap).
See thread: haskell-unordered-containers#319
I know these libraries will at least fail with the changes because they have instances on `HashMap`,
which now need to be `HashMapT salt`:
quickcheck-instances-0.3.25.2.drv
semirings-0.6.drv
relude-0.7.0.0.drv
semigroupoids-5.3.5.drv
I did this by stubbing out unordered containers in a 100k loc codebase
to see what issues would come up in CI.
jappeace
force-pushed
the
add-typelevel-salt
branch
from
73fa02e to
89c4f40
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
(trying to get github workflow to give me CI).
Real PR is here: haskell-unordered-containers#321