Re: Merging nth, aref, and elt.

[Stephen J. Turnbull]

Stefan Monnier writes:
 > >> So it looks like there's nothing to be done. here :-)
 > > I think there is:
 > > - The efficiency of (setf (elt s i) v) needs to be improved.
 > > - I'd argue that `elt' should also work on hash tables.
 > 
 > A few more steps, and `elt' becomes foo-get.

`get' should just work on everything.  (It's a shame getf has a
conflicting definition.)

But note that (get not-necessarily-symbolp-obj 0) has a gotcha: for
sequences 0 means the first object when iterating, for hashes and
symbols it means the value of the mapping at the object which
represents the integer 0 (which happens to be unique in Lisp).  So
it's potentially ambiguous.