History of Lenses

lens didn't just come out of the aether fully formed, it was a result of many people having many ideas over a long time. Here are a few of the revelations, reading about them may help understand the ideas and concerns of the library.

Jeremy Gibbons and Bruno C. d. S. Oliveira demonstrate that Traversals encode the Iterator pattern

The Essence of the Iterator Pattern

Luke Palmer creates a pattern he calls Accessors to ease stateful programming in Haskell

(wayback)Making Haskell nicer for game programming

Luke Palmer refines the notion of Accessors into something more like lenses

(wayback)Haskell State Accessors (second attempt: Composability)

Twan van Laarhoven comes up with a novel way to express lenses

CPS based functional references

Russel O'Connor realises such lenses can support polymorphic update

Polymorphic Update with van Laarhoven Lenses

Edward Kmett realises that by changing the constraint on the Functor, it is possible to have lens-like things like Getters, Setters, and Traversals

Mirrored Lenses