Lenses

Haskell's Lens type generalizes properties (i.e. accessors/mutators) found in other programming languages. For example, C# provides language support to treat properties as ordinary variables: class Point { public double x { get; set; } public double y { get; set; } } class Circle { public Point center { get; set; } public double radius { get; set; } } public void goRight(ref Circle c) { c.center.x

[SWIMATH2]

Lensというのを使うとフィールドへのアクセスがきれいになるらしい（？）。圏論出てきてよく分からんくなった

[perezvon]

Lens