Jean Abou Samra <j...@abou-samra.fr> writes: > Le 30/12/2021 à 12:36, Lukas-Fabian Moser a écrit : >> It's much worse than that: It's not the first time _I've_ been >> tripped up by this (previously it was with sort!). I'll just have to >> write 100 copies of >> >> "The exclamation mark in something! does not mean the function is >> guaranteed to make the desired change in-place." >> >> on my wall. > > > :-) > > For assoc-set! and friends, I actually wonder why this > is since when the function has exhausted the alist in > its search for a matching pair, it could well set the > last cdr to add the new pair at the end.
An empty list does not have a last cdr. -- David Kastrup
