RosettaCodeData/Task/Loop-over-multiple-arrays-simultaneously/TXR/loop-over-multiple-arrays-simultaneously-5.txr

(macro-time
  (defun question-var-to-meta-num (var)
    ^(sys:var ,(int-str (cdr (symbol-name var))))))

(defmacro map (square-fun . square-args)
  (tree-bind [(fun . args)] square-fun
    ^[apply mapcar (op ,fun ,*[mapcar question-var-to-meta-num args])
            (macrolet ([(. args) ^(quote ,args)])
               (list ,*square-args))]))

(defun word (. items)
  [apply format nil "~a~a~a" items])

(defun show (x) (pprinl x))

(show (map [(word ?1 ?2 ?3)] [a b c] [A B C] [1 2 3]))