Over the summer, Lucas Ma has been investigating ideas surrounding using effects in the OCaml compiler itself. He’s blogged some of his discoveries and adventures. The technical core of this work leads towards being able to use the OCaml compiler as a library on-demand to create a longer-lived “compiler service”. Of itself, that’s not at all revolutionary, but it is quite hard to do that with a 30 year old codebase that really was designed for single-shot separate compilation.