STMContainers.Set

Documentation

data Set e

A hash set, based on an STM-specialized hash array mapped trie.

type Element a = (Eq a, Hashable a)

A standard constraint for elements.

new :: STM (Set e)

Construct a new set.

insert :: Element e => e -> Set e -> STM ()

Insert a new element.

delete :: Element e => e -> Set e -> STM ()

Delete an element.

lookup :: Element e => e -> Set e -> STM Bool

Lookup an element.

focus :: Element e => StrategyM STM () r -> e -> Set e -> STM r

Focus on an element with a strategy.

This function allows to perform simultaneous lookup and modification.

The strategy is over a unit since we already know, which element we're focusing on and it doesn't make sense to replace it, however we still can still decide wether to keep or remove it.

foldM :: (a -> e -> STM a) -> a -> Set e -> STM a

Fold all the elements.

null :: Set e -> STM Bool

Check, whether the set is empty.