It really depends on what your idea of applied is, but Conal Elliot's work is really interesting. His paper on Compiling to Categories [1] pitches programming

It really depends on what your idea of applied is, but Conal Elliot's work is really interesting. His paper on Compiling to Categories [1] pitches programming language semantics as a cartesian closed category [2] allows for really cool stuff by mapping typical evaluation semantics to alternatives like building a computational graph visualization, a pretty printer, and imbuing the original program with automatic differentiation capabilities purely through the categorical interpretation of the same program. Essentially, if you can formulate a desired output of the program as a cartesian closed category, you can do it quite easily. [1]: http://conal.net/papers/compiling-to-categories/ http://conal.net/papers/compiling-to-categories/ [2]: A cartesian category with is a category with an operation that lets you pair things together into a new object and get out the original parts with eliminators. Think construct a tuple and have the ability to get the first and second elements out of the tuple. A cartesian closed category adds in the ability to model (partial) function application to its arguments via "apply, curry, and uncurry." See https://en.wikipedia.org/wiki/Cartesian_closed_category https://en.wikipedia.org/wiki/Cartesian_closed_category