implement some guards on the client. definitely need to relearn how to do syntax macros now...

client.rkt

@@ -30,6 +30,10 @@
     (super-new)
 
     (define/public (up-cmd)
+      (if (null? current-url)
+
+          (displayln "you need to 'go' somewhere first!")
+
           (if (string=?  (path->string
                           (simplify-path
                            (url->path current-url)))
@@ -42,7 +46,7 @@
                       (build-path (url->path current-url) 'up)
                       #f)])
                 (get (struct-copy url current-url
-                              [path (url-path (path->url parent))])))))
+                                  [path (url-path (path->url parent))]))))))
 
       (define/public (go-cmd url-string)
         (if (non-empty-string? url-string)
@@ -62,15 +66,19 @@
               (displayln (read-line document-buffer))
               (iter (sub1 depth)))))
 
+        (if (null? document-buffer)
+            (displayln "you need to 'go' somewhere first!")
+            (let ()
               (iter 10)
               (newline)
               (let ([remaining (pipe-content-length document-buffer)])
-        (printf "~a bytes remaining\n" remaining)))
+                (printf "~a bytes remaining\n" remaining)))))
 
       (define/public (visit-cmd line)
-      (define url (gmi:match-link document-object line))
-
-      (get (combine-url/relative current-url (url->string url))))
+        (if (null? document-object)
+            (displayln "you need to 'go' somewhere first!")
+            (let ([url (gmi:match-link document-object line)])
+              (get (combine-url/relative current-url (url->string url))))))
 
       (define/private (get url)
         (define (iter url depth)
@@ -93,6 +101,7 @@
               [(and (>= status 20)
                     (<= status 29))
 
+
                (let-values ([(doc) (gmi:parse (port->lines c-in))]
                             [(db-in db-out) (make-pipe #f)])