isetl was what we used for my discrete math course 20 years ago or so. I remember other students complaining about having to learn it. "when are we going to use this language".

Same and I hated it, tbh (but my experience was like 30 years ago). My prof insisted all work be done in SETL and did a terrible job of actually introducing us to the language, yet we had to submit our work as SETL code. Like, yay set theory, but I learned more implementing my homework in C and SmallTalk.