From Newsgroup: comp.lang.scheme

B. Pym wrote:

Rainer Joswig wrote:

(LOOP FOR x IN list-for-xs AND y IN list-for-ys
COLLECT (my-function a y x b))

(define x-list '(x0 x1 x2 x3))
(define y-list '(y0 y1 y2 y3))

(map (cut list '! <> '! <>) x-list y-list)

===>
((! x0 ! y0) (! x1 ! y1) (! x2 ! y2) (! x3 ! y3))

(define x-list '(x0 x1 x2 x3))
(define y-list '(y0 y1 y2 y3))

(% map (list '-- A: '-- B:) x-list y-list)

===>
((-- x0 -- y0) (-- x1 -- y1) (-- x2 -- y2) (-- x3 -- y3))

Given:

;; Anaphoric macro to abbreviate lambdas for higher-order functions.
;; Uses "_" for 1 argument;
;; uses "A:" and "B:" and so on for 2 or more arguments.
;; This version works under both Gauche Scheme
;; and Racket. Racket needs:
;; (require compatibility/defmacro)
;;
(define-macro %
(case-lambda
((func expr List) `(,func (lambda(_) ,expr) ,List))
((func expr . more)
(let* ((n 64)
(nums (map (lambda _ (set! n (+ 1 n)) n) more))
(vnames
(map (lambda(n)
(string->symbol (string (integer->char n) #\:)))
nums)))
`(,func (lambda ,vnames ,expr) ,@more)))))
--
[T]he problem is that lispniks are as cultish as any other devout group and basically fall down frothing at the mouth if they see [heterodoxy].
--- Kenny Tilton
The good news is, it's not Lisp that sucks, but Common Lisp. --- Paul Graham --- Synchronet 3.21a-Linux NewsLink 1.2