GADT allows us to reify a constraint as an explicit dictionary. With ConstraintKinds, we can further generalize this trick. In this post, I will explain how this trick works.

Overlapping instances are one of the most controversial features in Haskell. Fortunately, there are many tricks that let us avoid overlapping instances. In this post, I will introduce one such trick which uses closed type families.

Hello, Haskellers! Today I am going to explain what context reduction is and why it is necessary.

GHCi has a lesser known option :set +s. When turned on, GHCi displays some stats for each expression evaluated.

Multi-parameter type classes and functional dependencies made type-level programming possible. Back in 2000, Thomas Hallgren showed an implementation of insertion sort as an example of static computation using functional dependencies. The code has a strong resemblance to logic programming which looks bizarre to most functional programmers. In this post, I will show you a more “functional-style” implementation of insertion sort using closed type families.