brokkr-hashtables missing pieces

Utils.hs

module Utils (module Utils) where

import Brokkr.HashTable qualified as HT

import Control.Monad
import Control.Monad.Primitive

import Data.Hashable (hashWithSalt)

instance HT.Hash ShortText where
  hash txt = HT.HashFn (\st -> hashWithSalt st txt)

alterM :: (PrimMonad m, Eq k, HT.Hash k) => HashTable (PrimState m) k v -> (Maybe v -> m (Maybe v)) -> k -> m ()
alterM ht f k =
  HT.lookup
    ht
    k
    (\v -> f (Just v) >>= \case Nothing -> void (HT.delete ht k); Just v' -> HT.insert ht k v')
    (f Nothing >>= \case Nothing -> pure (); Just v' -> HT.insert ht k v')
{-# INLINE alterM #-}

-- for this benchmark we don't need the ability to be able to delete and usage of this leads to a bit better results (1-2%)
-- to be honest, I am in the realm of microoptimizations at this point :)
alterM' :: (PrimMonad m, Eq k, HT.Hash k) => HashTable (PrimState m) k v -> (Maybe v -> m v) -> k -> m ()
alterM' ht f k = HT.lookup ht k (\v -> f (Just v) >>= HT.insert ht k) (f Nothing >>= HT.insert ht k)
{-# INLINE alterM' #-}