Subject: bug#75170: add-to-alist: new function

From: Drew Adams <[email-masked]>
Date: Tue, 21 Jan 2025 22:53:11 +0000

> The test for presence of the car of ELT-CONS is done
> with `equal'."
>   (assoc (car elt-cons) (symbol-value alist-var))

Seems like you should consider adding an optional
TESTFN arg for the equality predicate.  There's a
reason Lisp has had both `assq' and `assoc' since
forever.  And there's a reason that `assoc' itself
later began to accept such an optional arg.