My name is John, and I’m a senior software engineer at Mercury, a fintech company, where I mostly write Haskell. Before this I was an engineer at Facebook for 10 years, where I initially learned Haskell (writing rules in Sigma, and then later leading a data-processing project that used Haskell at its core, but unfortunately didn’t publish anything externally), but mostly wrote PHP and C++.

As I learn more Haskell, and use it in more and varied circumstances, I run into potentially interesting things and thought it made sense to start writing them down so that others may benefit.