OUTDATER added; URL tag accepts more text fields now

scheme/httpd/surflets/surflets.scm

@@ -144,7 +144,10 @@
 
 (define URL-rule
   (cons 'URL 
-	(lambda (tag URI text) (list "<a href=\"" URI "\">" text "</a>"))))
+	(lambda (tag URI . maybe-text) (list "<a href=\"" URI "\">" 
+					     (if (pair? maybe-text)
+						 maybe-text
+						 URI)"</a>"))))
 
 (define default-rules
  `(,attribute-rule
@@ -163,10 +166,34 @@
 
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; outdater
 
+(define-record-type outdater :outdater
+  (real-make-outdater outdated?)
+  outdater?
+  (outdated? outdater-outdated? set-outdater-outdated?!))
 
+(define (make-outdater)
+  (real-make-outdater #f))
 
+(define-syntax if-outdated
+  (syntax-rules ()
+    ((if-outdated outdater consequence alternative)
+     (if (outdater-outdated? outdater)
+	 consequence
+	 (begin
+	   (set-outdater-outdated?! outdater #t)
+	   alternative)))))
 
+(define (show-outdated url)
+  (send-html 
+   `(html (title "Outdated Data")
+	  (body (h1 "Outdated Data")
+		(p "The page or action you requested relies on outdated data")
+		(p "Try to " 
+		   (URL ,url "reload") 
+		   " the page to get current data.")))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; input-fields