When I first encountered the concept of an adjunction, I got quite confused as to what it is, and why it is useful: Just how on earth is a left adjoint of a functor? What’s the matter of a free and forgetful functor, why is free left to forgetful but not the other way round. That’s where this blog comes from. I hope this blogpost can help demystify adjunction for you a little bit....
This article is very much my attempt to understand monad as a design pattern in programming languages and why on earth it is useful. There are tons of monad tutorials online, but I found relatively few ones argue for the usefulness of a monad by having side by side code examples that achieve similar functionalties. If you found one, please do let me know! I try to draw connections between monads’ original mathematical definition and its actual usage so that this mysterious concept does not come out of the blue....