Pointwise Lenses

Posted on April 24, 2014

Lenses are a current hot topic in the Haskell community, with a bunch of packages providing implementations (data-accessor, fclabels, lens, amongst others). Although we will recall definitions, this post is not meant as an introduction to lenses. If you have not worked with lenses before, the talk from Simon Peyton Jones or the blog post by Sebastiaan Visser about fclabels are good starting points.

In this blog post we will propose a generalization to the lens representation used in fclabels and in many other packages (with various minor variations); we will consider the relation to the representation used in lens in a separate section.

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