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 non-portable
Safe Haskell Trustworthy
Language Haskell2010

Data.Vector.Lens

Description

This module provides lenses and traversals for working with generic vectors.

Synopsis

Documentation

toVectorOf :: Getting ( Endo [a]) s a -> s -> Vector a Source #

Similar to toListOf , but returning a Vector .

>>> toVectorOf both (8,15) == Vector.fromList [8,15]
True

Isomorphisms

vector :: Iso [a] [b] ( Vector a) ( Vector b) Source #

Convert a list to a Vector (or back)

>>> [1,2,3] ^. vector == Vector.fromList [1,2,3]
True
>>> [1,2,3] ^. vector . from vector
[1,2,3]
>>> Vector.fromList [0,8,15] ^. from vector . vector == Vector.fromList [0,8,15]
True

forced :: Iso ( Vector a) ( Vector b) ( Vector a) ( Vector b) Source #

Convert a Vector to a version that doesn't retain any extra memory.

Lenses

sliced Source #

Arguments

:: Int

i starting index

-> Int

n length

-> Lens' ( Vector a) ( Vector a)

sliced i n provides a Lens that edits the n elements starting at index i from a Lens .

This is only a valid Lens if you do not change the length of the resulting Vector .

Attempting to return a longer or shorter vector will result in violations of the Lens laws.

>>> Vector.fromList [1..10] ^. sliced 2 5 == Vector.fromList [3,4,5,6,7]
True
>>> (Vector.fromList [1..10] & sliced 2 5 . mapped .~ 0) == Vector.fromList [1,2,0,0,0,0,0,8,9,10]
True

Traversal of individual indices

ordinals :: [ Int ] -> IndexedTraversal' Int ( Vector a) a Source #

This Traversal will ignore any duplicates in the supplied list of indices.

>>> toListOf (ordinals [1,3,2,5,9,10]) $ Vector.fromList [2,4..40]
[4,8,6,12,20,22]