This question is answered immediately in the linked video.

this takes a lot longer to type than before or after

11 minutes in, he mentions SICP as a book that he ended up working through exercises "in the past year" (so 2012 timeframe, well after the original Doom but before the reboot).

Thank you! :) Provides helpful context vis-a-vis evaluating possible critical-path enabling / contributing factors to achieving a key milestone.

Think how long it would have taken to click the link!

(About 9 minutes, acc. to the parallel subthread. My time on this thread is about 90 seconds so far not incl this current comment.)

Still haven't clicked it, huh? If you did you'd see that the link takes you to straight to the moment in the video where he starts talking about functional programming.

I don't have time to watch the video right now, but according to gpt watching the video for me: after.