map a url to variable names, suggested by #emacs jaimef. like what sinatra does

bind-path.el

(defun elnode/bind-path (pattern httpcon)
  (let* ((path (elnode-http-pathinfo httpcon))
         (lst (split-string pattern "/" t))
         (patlst
          (let ((i 0))
            (loop for part in lst
               if (string-match-p "^:.*" part)
               collect (cons i (intern (substring part 1)))
               do (setq i (+ 1 i)))))
         (splt (split-string path "/")))
    (let ((i 0))
      (loop for part in splt
         if (aget patlst i)
         collect (cons (aget patlst i) (list part))
         do (setq i (+ i 1))))))

(defmacro elnode-bind-path (pattern httpcon &rest body)
  (declare (indent 2))
  `(let (,@(elnode/bind-path pattern httpcon))
     ,@body))

;; Demo of the underlying func
(flet ((elnode-http-pathinfo (httpcon) "/one/a/b"))
  (elnode/bind-path "/one/:one/:two" :httpcon))

;; Now the macro
(flet ((elnode-http-pathinfo (httpcon) "/one/a/b"))
  (pp-macroexpand-expression
   '(elnode-bind-path "/one/:one/:two" :httpcon
     (+ 1 2))))

Works if the omit-nulls parameter is dropped from the first split-string