lens-3.8.7.3: Lenses, Folds and Traversals

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

Data.Set.Lens

Description

Synopsis

- setmapped :: (Ord i, Ord j) => IndexPreservingSetter (Set i) (Set j) i j
- setOf :: Getting (Set a) s t a b -> s -> Set a

# Documentation

setmapped :: (Ord i, Ord j) => IndexPreservingSetter (Set i) (Set j) i j

This `Setter` can be used to change the type of a `Set` 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`.

    >>> over setmapped (+1) (fromList [1,2,3,4])
    fromList [2,3,4,5]

setOf :: Getting (Set a) s t a b -> s -> Set a

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

    >>> setOf folded ["hello","world"]
    fromList ["hello","world"]

    >>> setOf (folded._2) [("hello",1),("world",2),("!!!",3)]
    fromList [1,2,3]

     setOf ::          Getter s a     -> s -> Set a
     setOf :: Ord a => Fold s a       -> s -> Set a
     setOf ::          Iso' s a       -> s -> Set a
     setOf ::          Lens' s a      -> s -> Set a
     setOf :: Ord a => Traversal' s a -> s -> Set a