This is part of a wry joke at the expense of LISPers and lambda calculators:
"... the heretic is chained in the dungeon where he is forced to learn Common Lisp on a Commodore 64 and interact with rapacious Lemmy-ings and Mastodonians."
Updated my ugly-ass lambda calculus thing on my website (https://www.iguanasuicide.net/) and now you can click the name of the reduction to perform it.
Writing complex #XPath expressions to emulate if-then-else using substrings, lists and indexing using boolean conditions... feels like #LambdaCalculus but a lot worse :'D