#! /bin/sh 
string=? ; exec mzscheme -M errortrace -gr $0 $* 
;   http://pair.com/lisovsky/transform/examples/ 

(require (lib "sxml-tools.ss" "sxml")
	 (lib "sxpath.ss" "sxml")
	 (lib "13.ss" "srfi")
	 (lib "common.ss" "sxml")
	 (lib "myenv.ss" "ssax")
 	 (lib "stx-engine.ss" "sxml")
	 (lib "fragments.ss" "sxml"))

; Read thw document to transform
(define doc (read (open-input-file "mail.sxml")))

; A "demo" spam filter: any email which contains % character in subject
; is considered spam. 
; You can use _any_ Scheme function instead of this one-liner.
; For real filtering a Bayesian filter
;  http://www.shiro.dreamhost.com/scheme/vault/scbayes.tgz
; is worth a consideration
(define (is-spam? msg)
    (string-contains ((car-sxpath '(subject *text*)) msg) "%"))
 
; Transformation stylesheet
(define sst
(sxml:stylesheet
  (match 'mailbox 
	 (lambda (current-node stx:templates current-root $)
           `(html 
	     (head (title "Mail messages"))
	     (body 
	       (h1 "E-mail subjects: ")
	        (ol
		  ,@(xsl:apply-templates))))))
  (match  'msg
	 (lambda (current-node stx:templates current-root $)
	   `(li
             ,@(if (is-spam? current-node)   ; if the message is spam
		 '("[SPAM] ")                ; insert the tag
		 '())
	      ,((car-sxpath '(subject *text*)) current-node))
	   ))
  ))

; Do the transformation and print out HTML output 
  (sxml:display-fragments
    (sxml:sxml->html
      (stx:apply-templates doc      ; document
			   sst      ; stylesheet
			   doc      ; root
			   '())))   ; var bindings