lens-5.0.1: Lenses, Folds and Traversals
Copyright (C) 2012-16 Edward Kmett
License BSD-style (see the file LICENSE)
Maintainer Edward Kmett <ekmett@gmail.com>
Stability provisional
Portability portable
Safe Haskell Safe-Inferred
Language Haskell2010

Data.IntSet.Lens

Description

Synopsis

Documentation

members :: Fold IntSet Int Source #

IntSet isn't Foldable, but this Fold can be used to access the members of an IntSet .

>>> sumOf members $ setOf folded [1,2,3,4]
10

setmapped :: IndexPreservingSetter' IntSet Int Source #

This Setter can be used to change the contents of an IntSet by mapping the elements to new values.

Sadly, you can't create a valid Traversal for a Set , because the number of elements might change but you can manipulate it by reading using folded and reindexing it via setmapped .

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

setOf :: Getting IntSet s Int -> s -> IntSet Source #

Construct an IntSet from a Getter , Fold , Traversal , Lens or Iso .

>>> setOf folded [1,2,3,4]
fromList [1,2,3,4]
>>> setOf (folded._2) [("hello",1),("world",2),("!!!",3)]
fromList [1,2,3]
setOf :: Getter s Int     -> s -> IntSet
setOf :: Fold s Int       -> s -> IntSet
setOf :: Iso' s Int       -> s -> IntSet
setOf :: Lens' s Int      -> s -> IntSet
setOf :: Traversal' s Int -> s -> IntSet