lens-3.8.7.3: Lenses, Folds and Traversals

Portability | portable
Stability | provisional
Maintainer | Edward Kmett <ekmett@gmail.com>
Safe Haskell | Trustworthy

Data.HashSet.Lens

Description

Synopsis

- setmapped :: (Eq i, Hashable i, Eq j, Hashable j) => IndexPreservingSetter (HashSet i) (HashSet j) i j
- setOf :: Hashable a => Getting (HashSet a) s t a b -> s -> HashSet a

# Documentation

setmapped :: (Eq i, Hashable i, Eq j, Hashable j) => IndexPreservingSetter (HashSet i) (HashSet j) i j

This `Setter` can be used to change the type of a `HashSet` by mapping the elements to new values.

Sadly, you can't create a valid `Traversal` for a `Set`, but you can manipulate it by reading using `folded` and reindexing it via `setmapped`.

setOf :: Hashable a => Getting (HashSet a) s t a b -> s -> HashSet a

Construct a set from a `Getter`, `Fold`, `Traversal`, `Lens` or `Iso`.

     setOf :: Hashable a         => Getter s a     -> s -> HashSet a
     setOf :: (Eq a, Hashable a) => Fold s a       -> s -> HashSet a
     setOf :: Hashable a         => Iso' s a       -> s -> HashSet a
     setOf :: Hashable a         => Lens' s a      -> s -> HashSet a
     setOf :: (Eq a, Hashable a) => Traversal' s a -> s -> HashSet a