# Lens (functional programming)¶

## Backlinks¶

- Lenses can be seen as a bijection with some residual
- A
`Lens a b`

is a bijection between a and (b, r), where r is a - b. This represents a Lens as an isomorphism. Given (b, r) one could construct a.

- A

- Lenses can be seen as a bijection with some residual
- A
`Lens a b`

is a bijection between a and (b, r), where r is a - b. This represents a Lens as an isomorphism. Given (b, r) one could construct a.

- A