http://the.domain.com/pagename/p1/p2/p3?param1=value1

(s:get-page-params) => '("p1" "p2")

(s:get-param 'param1) => "value1"
(s:get-param 'param1 'number) => number or #f 

NOTE: it is often practical to use the generic (s:get-inp ...) which
      will first look for the POST input variable and then fall back
      to the GET param. This allows one to switch back and forth
      between GET and POST during development without changing the code.

(s:get-inp 'param1)  ;; trys to find input by name of param1, followed by trying get-param

Create a link.
~~~~~~~~~~~~~~

(s:a name 'href 
    (s:link-to "pagename/blah" ""))

Call current page with new param

	(let ((newresult (cons (string-append (s:any->string key) "=" (s:any->string val))
			       result)))
	  (if (< (length tail) 1) ;; true if done
	      (string-intersperse newresult "&")
	      (loop (car tail)(cadr tail)(cddr tail) newresult))))))

(define (session:link-to self page params)
  (let* ((server    (if (get-environment-variable "HTTP_HOST")
  (let* ((server    (or (get-environment-variable "HTTPS_HOST") ;; Assuming HTTPS_HOST is only set if available
			(get-environment-variable "HTTP_HOST")
			(get-environment-variable "SERVER_NAME")))
         (force-script  (sdat-get-script self))
	 (script (or force-script
                     (let ((script-name (string-split (get-environment-variable "SCRIPT_NAME") "/")))
                       (if (> (length script-name) 1)
                           (string-append (car script-name) "/" (cadr script-name))

			  "\r")
			 "\\r")
			res)) ;; should return #f if not a string and can't escape it?
      (else      (if (string? res)
		     (s:html-filter->string res '())
		     res)))))

;; params are stored as list of key=val
;;
(define (session:get-param self key type-params)
  ;; (session:log s:session "params=" (slot-ref s:session 'params))
  (let* ((params (sdat-get-params self))
	 (res    (session:get-param-from params key)))
    (session:apply-type-preference res type-params)))

;; This one will get the first value found regardless of form

;;
(define (s:get-input key . params)
  (session:get-input s:session key params))

(define (s:get-input-keys)
  (session:get-input-keys s:session))

;; get-input else, get-param else #f
;;
(define (s:get-inp key . params)
  (or (apply s:get-input key params)
      (apply s:get-param key params)))

(define (s:load-model model)
  (session:load-model s:session model))

(define (s:model-path model)
  (session:model-path s:session model))

;; share data between pages calls. NOTE: This is not persistent