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> Michael Sperber <sperber@xxxxxxxxxxxxxxxxxxxxxxxxxxx> writes: > >>>>>> "Will" == Will Fitzgerald <fitzgerald@xxxxxxxxxxxx> writes: > > > >Will> May I suggest the following addition to the SRFI-1 list library, > >Will> Common Lisp's LDIFF: > > > >Will> I think a reasonable definition is: > >Will> [...] > >[...] > >Could you suggest possible uses for this procedure? Here's a fairly trivial use taken from a real program: (define parse-signature (lambda (spec) (let* ((mid (memq '- spec)) (in (list-difference spec mid)) (out (cdr mid))) (make-signature in out)))) And here's another: (define (butlast L) (list-difference L (last-pair L))) But groveling through my source directories reveals fewer instances of list-difference than I expected. -Darius