A few days ago, I stumbled on a repository on GitHub that was exploring category theory through the use of Coq, formalizing Edware Kmett’s Hask library. Curious, I wondered what Hask was and read the description: “Category theory for Haskell with a lens flavor”.
But… what are lenses?
I remembered that I had bookmarked a blog post that Steve Klabnik tweeted a while ago because it was related to Haskell. And now it was relevant to my interests.
Lenses are, at a high level, something like “getters” and “setters” that are used in imperative programming languages. It’s not uncommon to see something like
book.author.name. Lenses provide an abstraction like this for Haskell.
I spent a long time staring at the explanations in this blog post, and after pairing with Alan a bit on a simple Lens implementation, felt blown away by the weirdness and how elegant of an idea this was.
A realization that I had about working with Alan (after ten weeks…) is that he is the type of person to think things out by writing on a white board. Up until this point, I had never really thought about whiteboarding as a way of getting my thoughts out so that I could actually look at them. And the act of writing type signatures out instead of staring at them on a screen made a lot of difference for me. (I do write on scratch paper, but I generally do so very disorganizedly).
After Thursday demo presentations, I spent about thirty minutes whiteboarding out my thought process for the implementations of
I guess moral of the story for me is that I should whiteboard more to figure out what I’m doing when I’m confused before jumping straight to code. A very simple epiphany, but a very helpful one.