Implement quoted-printable conversion.

src/util-mail.scm

@@ -35,6 +35,7 @@
  (import scheme
 	 (chicken base)
 	 (chicken keyword)
+	 (chicken string)
 	 util-io
 	 util-string)
 
@@ -43,8 +44,14 @@
 
  ;; Encodes given UTF-8 string as quoted-printable
  (define (string->qp str)
-   (let ((lst (string->list/utf8 str)))
-     str))
+   (let loop ((lst (string->list/utf8 str))
+	      (res '()))
+     (if (null? lst)
+	 (string-intersperse (reverse res) "")
+	 (loop (cdr lst)
+	       (cons (let ((chs (car lst)))
+		       chs)
+		     res)))))
 
  ;; Ensures the subject has proper encoding
  (define (encode-subject subj)