*add comment explaining why we don't need to support "*" and authority

Request-URIS
*comment on when unescaping is done
*don't unescape query when building a http-url record
*don't escape query when unparsing a http-url record.
*remove PARSED-URI->HTTP-URL, integrate its code into
URL-STRING->HTTP-URL
*add dummy encoder ESCAPE-NOT-UNRESERVED-CHARS

scheme/lib/url.scm

@@ -43,6 +43,12 @@
 ;;; Request-URI    = ( http_URL | abs_path ["?" query] ) ["#" fragment]
 
 
+;;; Note: we don't have to support Request-URIS of the form "*" or
+;;; authority, because these are not used with the any of the methods
+;;; HEAD, GET and POST, which are the only methods we implement so
+;;; far.
+
+
 ;;; Here we depart from the RFCs:
 ;;; RFC 2616 and 1945 disallow a #fragment-suffix of the Request-URI.
 ;;; For compatibility with buggy clients we _do_ allow for it.
@@ -159,7 +165,8 @@
 ;;; If there's no abs_path given, or abs_path is "/", path is the empty list;
 ;;; otherwise it is a list containing the path's segments.
 ;;;
-;;; don't decode yet!
+
+;;; Caution: parse-url doesn't unescape anything yet!
 
 (define (parse-url request-uri)
    (cond 
@@ -214,9 +221,14 @@
 ;;;
 ;;; The PATH slot is the Request_URI's path split at slashes
 ;;; (e.g., "/foo///bar//baz/" => ("foo" "bar" "baz")) 
-;;; and decoded. 
+;;; and unescaped. 
 ;;;
-;;; The QUERY slot is a decoded non-empty-string or #f.
+;;; The QUERY slot is an non-empty-string, still in its escaped
+;;; representation, or #f.
+
+;;; Caution: the path slot of a http-url record has already been
+;;; UNESCAPED; don't unescape it a second time!
+;;; The query slot is still in its escaped representation.
 
 (define-record-type http-url :http-url
   (make-http-url host port path query)
@@ -226,24 +238,16 @@
   (path http-url-path)
   (query http-url-query))
 
-;;; decode various parts of the Request_URI as returned by PARSE-URL;
-;;; returns a HTTP-URL record.
-
-(define (parsed-uri->http-url host port path query)
-
-  (let 	((portnumber (and port (string->number port)))
-	(decoded-path (map unescape path))
-	(decoded-query (and query (unescape query))))
-
-  (make-http-url host portnumber decoded-path decoded-query)))
-
 
 ;;; parse a HTTP 1.1. Request_URI into a http-url record
 
 (define (url-string->http-url uri-string)
-  (call-with-values
-   (lambda () (parse-url uri-string))
-   parsed-uri->http-url))
+  (receive (host port path query)
+	   (parse-url uri-string)
+	   (let ((portnumber (and port (string->number port)))
+		 (unescaped-path (map unescape path)))
+	     (make-http-url host portnumber unescaped-path query))))
+  
 
 ;;; Unparse a http-url record into its corresponding Request_URI
 
@@ -271,7 +275,7 @@
 
 	(query (http-url-query http-url))
 	(query-string (if query
-			(string-append "?" (escape-query query))
+			(string-append "?" query)
 			"")))
 
     (string-append scheme-and-host-string port-string path-string query-string)))
@@ -309,6 +313,10 @@
 (define (escape-query query)
   (escape query query-reserved-and-excluded))
 
+;;; encode something we don't know: escape all but the unreserved characters.
+(define (escape-not-unreserved-chars something)
+  (escape something (rx (~ ,unreserved))))
+
 ;; Appendix A of RFC 2396
 ;;
 ;A. Collected BNF for URI