lens-1.4.1: Lenses, Folds and Traversals
Data.Pair.Lens
Description
Lenses for working with products.
Due to their ubiquity, _1 and _2 are defined in Control.Lens.
_1
_2
Control.Lens
Synopsis
both :: Traversal (a, a) (b, b) a bSource
Traverse both parts of a tuple with matching types.
value :: (k -> Bool) -> Simple Traversal (k, v) vSource
This provides a Traversal that checks a predicate on a key before allowing you to traverse into a value.
Traversal