All you need is λ, part one: booleans

Nearly a century ago, Alonzo Church invented the simple, elegant, and yet elusive lambda calculus. Along with Alan Turing, he then proved the Church-Turing thesis: that anything computable with a Turing machine can also be computed in the lambda calculus. However, nearly as soon as we had digital computers, we started inventing programming languages, and with them a vast treasure of features, beautiful and terrible, many of which seem very hard to relate to the fundamental nature of computability, let alone the lambda calculus specifically.

Pattern matching over recursive values in Swift

Swift’s value types are almost able to represent algebraic data types. Unfortunately, they fall short of the mark when it comes to recursion, and while they’ve announced that their solution, indirect cases, will ship in a later build of Swift 2, there’s still reason to want them today.

On the Order of Neptune

Inscribe the orbit of Neptune in a square.