Optics are bidirectional data accessors that capture data transformation patterns such as
accessing subfields or iterating over containers. Profunctor optics are a particular choice of …

Type inference is essential for statically-typed languages such as OCaml and Haskell. It can
be decomposed into two (possibly interleaved) phases: a generator converts programs to …

There are different notions of computation, the most popular being monads, applicative
functors, and arrows. In this article, we show that these three notions can be seen as …

Optics are bidirectional accessors of data structures; they provide a powerful abstraction of
many common data transformations. This abstraction is compositional thanks to a …

Representation theorems relate seemingly complex objects to concrete, more tractable
ones. In this paper, we take advantage of the abstraction power of category theory and …

To lighten the burden of programming language mechanization, many approaches have
been developed that tackle the substantial boilerplate which arises from variable binders …

Verifying the metatheory of a formal system in Coq involves a lot of tedious" infrastructural"
reasoning about variable binders. We present Tealeaves, a generic framework for first-order …

We present new ways of reasoning about a particular class of effectful Haskell programs,
namely those expressed as idiomatic traversals. Starting out with a specific problem about …

Traversing an algebraic datatype by hand requires boilerplate code which duplicates the
structure of the datatype. Datatype-generic programming (DGP) aims to eliminate such …

An effectful traversal of a data structure iterates over every element, in some predetermined
order, collecting computational effects in the process. Depth-first effectful traversal of a tree is …