The Grinnell Scheme Web: The assq procedure

And I suppose there's an analogue of assoc that uses eq? rather than equal?.

Yes, there is. It's called assq. It takes an object and an association list, and returns the first pair on the association list in which the car is eq? to the object, or #f if there is no such pair:

> (assq #f '((#t . 17) (#f . 39)))
(#f . 39)
> (assq 17  '((#t . 17) (#f . 39)))
#f
> (assq #t '())
#f

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created December 30, 1995
last revised January 3, 1996