Store command line arguments in parameters

param-args.ss

(define-syntax param-args
  (syntax-rules ()
    [(_ arg-list (opt param) ...)
      (let loop ([args arg-list])
        (if (null? args)
            '()
            (case (car args)
              [(opt) (if (null? (cdr args))
                         (errorf 'param-args "Missing required argument for ~a" opt))
                (param (cadr args))
                (loop (cddr args))] ...
              [else args])))]))

;;;
;;; Usage:
;;;
;;; (param-args some-arg-list
;;;   ["--foo" foo-param]
;;;   ["--bar" bar-param]
;;;   ["--baz" baz-param])
;;; 
;;; some-arg-list is a list of strings, like (command-line-arguments)
;;; if no matching options are found, the rest of the arguments are returned from the expression
;;; when an option matches, the corresponding function (foo-param, bar-baram, or baz-param) is called 
;;; with the next element of some-arg-list