Sure; here's something from my tagged-unions.arc on Anarki (Arc 2). It's responsible for parsing the types specified for slots in the tagged union:
(each type-frag types
; Assemble the ('type name) pairs into two lists, so that we can iterate
; through them.
(case (type type-frag)
; If it's a symbol, then we're defining a new name; add a new set of
; values, and go.
sym
(do
(zap [cons type-frag _] names)
(zap [cons nil _] values))
; Otherwise, we're adding a value to an existing variant.
cons
; I changed my mind about the order (now it's (name pred?) instead of
; (pred? name)), so I'm reversing it here.
(zap [cons (rev type-frag) _] (car values))
; else
(err "Invalid member of tagged union declaration.")))
I should also add (just as another data point) that my multi-condition ifs look like that too, and single-condition ifs look like the following:
(def macexn (n expr)
" Macroexpand `expr' `n' times. NB: `expr' *is* evaluated!
See also [[macex1]] [[macex]] "
(if (and (number n) (> n 0))
(macexn (- n 1) (macex1 expr))
expr))
I'm not hugely wedded to any of my conventions, though, and I haven't coded in Arc for quite a while anyway; this isn't intended to get you to change anything or convert people to my style. As I said, it's just another data point.
