Oh, it is not just CLOS. defstruct also defines setters and many an apparent reader function is also a writer, (so we call them accessors). That means one does not fire up (defun (setf foo)...) unless there is an usual case of abstraction where there is some function on an object (not just reading a slot) and where there is some state change intelligibly viewed as being transitive aka share the name with the reader.
In re writing a defun, I probably just talked you out of it, but here is what I did (warning, old nooby Arc code) for optional and keyword args:
(mac defun (name params . body)
(w/uniq (rtargs)
`(def ,name ,rtargs
(withs ,(with (reqs nil key? nil opt? nil keys nil opts nil without)
(each p params
(if (is p '&o) (do (assert (no opt?) "Duplicate &o:" ',params)
(assert (no key?) "&k cannot precede &o:" ',params)
(= opt? t))
(is p '&k) (do (assert (no key?) "Duplicate &k:" ',params)
(= key? t))
key? (push-end p keys)
opt? (push-end p opts)
(do (assert (~acons p) "Reqd parameters need not be defaulted:" p)
(push-end p reqs))))
(with (n -1 kvs (uniq))
(+ (mappend [list _ `(nth ,(++ n) ,rtargs)] reqs)
(mappend [list (carif _) `(or (nth ,(++ n) ,rtargs)
,(cadrif _))] opts)
(list kvs `(pair (nthcdr ,(++ n) ,rtargs)))
(mappend [list (carif _)
`(or (alref ,kvs ',(carif _))
,(cadrif _))] keys)
)))
,@body))))
also, i find myself not using clos or defstruct all that much in my cl code. i tend to use ordinary data structures like lists and arrays.
my recent example (an excerpt from which i already showed) was a sudoku solver. i wrote one version in CL, then thought i'd do it in arc for fun. in CL, the puzzles were simply arrays (in Arc, they were lists do to the lack of an array type).
However, i didn't want my code to use the array (or list) accessors built into the language to access values in the puzzle, because that is not abstract enough. so i defined a function called pval that takes the puzzle and an x and y, giving the value in that square. that way, my code deals with puzzles, not arrays.
Then I wanted to be able to set the value in a square using the same pval accessor. Trivial in CL, but Arc made it a little difficult. This comes up rather often for me.
That point might not have justified such a long explanation. Whoops.
all i really intend to do is a simple def= macro that will transform (def= pval (val puz x y) (= ((puz y) x) val)) into the previously given defset form. shouldn't be too bad. i have no intentions of mimicing CL's defun. i honestly like arc's def as it is.
