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

client.rkt

@@ -30,107 +30,116 @@
     (super-new)
 
     (define/public (up-cmd)
-      (if (string=?  (path->string
-                      (simplify-path
-                       (url->path current-url)))
-                    "/")
+      (if (null? current-url)
 
-          (displayln "already at root!")
+          (displayln "you need to 'go' somewhere first!")
 
-          (let ([parent
-                 (simplify-path
-                  (build-path (url->path current-url) 'up)
-                  #f)])
-            (get (struct-copy url current-url
-                              [path (url-path (path->url parent))])))))
+          (if (string=?  (path->string
+                          (simplify-path
+                           (url->path current-url)))
+                         "/")
 
-    (define/public (go-cmd url-string)
-      (if (non-empty-string? url-string)
-          (let ()
-            (when (not (string-contains? url-string "://"))
-              (set! url-string (string-append "gemini://" url-string)))
+              (displayln "already at root!")
 
-            (get (string->url url-string)))
+              (let ([parent
+                     (simplify-path
+                      (build-path (url->path current-url) 'up)
+                      #f)])
+                (get (struct-copy url current-url
+                                  [path (url-path (path->url parent))]))))))
 
-          (displayln "go where?")))
+      (define/public (go-cmd url-string)
+        (if (non-empty-string? url-string)
+            (let ()
+              (when (not (string-contains? url-string "://"))
+                (set! url-string (string-append "gemini://" url-string)))
 
-    (define/public (next-cmd)
-      (define (iter depth)
-        (when (and (> depth 0)
-                   (> (pipe-content-length document-buffer) 0))
-          (let ()
-            (displayln (read-line document-buffer))
-            (iter (sub1 depth)))))
+              (get (string->url url-string)))
 
-      (iter 10)
-      (newline)
-      (let ([remaining (pipe-content-length document-buffer)])
-        (printf "~a bytes remaining\n" remaining)))
+            (displayln "go where?")))
 
-    (define/public (visit-cmd line)
-      (define url (gmi:match-link document-object line))
+      (define/public (next-cmd)
+        (define (iter depth)
+          (when (and (> depth 0)
+                     (> (pipe-content-length document-buffer) 0))
+            (let ()
+              (displayln (read-line document-buffer))
+              (iter (sub1 depth)))))
 
-      (get (combine-url/relative current-url (url->string url))))
+        (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)))))
 
-    (define/private (get url)
-      (define (iter url depth)
-        (let-values ([(status header c-in) (net:request url)])
-          ;; TODO there are bunch of other status codes to deal with for
-          ;; compliance
-          (cond
-            ;; clients MUST reject status codes outside of the 10-69 range
-            [(or (< status 10)
-                 (> status 69))
-             (displayln "WARNING: server returned invalid status code")]
+      (define/public (visit-cmd line)
+        (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))))))
 
-            ;; 10-19 INPUT REQUIRED
-            [(and (>= status 10)
-                  (<= status 19))
-             (display "input requested > ")
-             (get (string-append url "?" (read-line)))]
+      (define/private (get url)
+        (define (iter url depth)
+          (let-values ([(status header c-in) (net:request url)])
+            ;; TODO there are bunch of other status codes to deal with for
+            ;; compliance
+            (cond
+              ;; clients MUST reject status codes outside of the 10-69 range
+              [(or (< status 10)
+                   (> status 69))
+               (displayln "WARNING: server returned invalid status code")]
 
-            ;; 20-29 SUCCESS
-            [(and (>= status 20)
-                  (<= status 29))
+              ;; 10-19 INPUT REQUIRED
+              [(and (>= status 10)
+                    (<= status 19))
+               (display "input requested > ")
+               (get (string-append url "?" (read-line)))]
 
-             (let-values ([(doc) (gmi:parse (port->lines c-in))]
-                          [(db-in db-out) (make-pipe #f)])
+              ;; 20-29 SUCCESS
+              [(and (>= status 20)
+                    (<= status 29))
 
-               (set! document-object doc)
 
-               (set! document-buffer db-in)
-               (parameterize ([current-output-port db-out])
-                 (gmi:render doc))
+               (let-values ([(doc) (gmi:parse (port->lines c-in))]
+                            [(db-in db-out) (make-pipe #f)])
 
-               (set! current-url url)
+                 (set! document-object doc)
 
-               (let ([remaining (pipe-content-length db-in)])
-                 (printf "document retrieved. ~a bytes\n" remaining))
+                 (set! document-buffer db-in)
+                 (parameterize ([current-output-port db-out])
+                   (gmi:render doc))
 
-               (next-cmd))]
+                 (set! current-url url)
 
-            ;; 30-39 REDIRECT
-            [(and (>= status 30)
-                  (<= status 39))
-             (if (> depth 5)
-                 (displayln "WARNING: maximum redirection depth exceeded")
-                 (iter (string->url header) (sub1 depth)))]
+                 (let ([remaining (pipe-content-length db-in)])
+                   (printf "document retrieved. ~a bytes\n" remaining))
 
-            ;; 40-49 TEMPORARY FAILURE
-            [(and (>= status 40)
-                  (<= status 49))
-             (printf "status ~a: ~a\n" status
-                     (dict-ref temporary-failures status "temporary failure"))]
+                 (next-cmd))]
 
-            ;; 50-59 PERMANENT FAILURE
-            [(and (>= status 50)
-                  (<= status 59))
-             (printf "status ~a: ~a\n" status
-                     (dict-ref permanent-failures status "permanent failure"))]
+              ;; 30-39 REDIRECT
+              [(and (>= status 30)
+                    (<= status 39))
+               (if (> depth 5)
+                   (displayln "WARNING: maximum redirection depth exceeded")
+                   (iter (string->url header) (sub1 depth)))]
 
-            ;; 60-69 CERTIFICATE REQUIRED
-            [(and (>= status 60)
-                  (<= status 69))
-             (displayln "certificate handling not yet implemented")])))
+              ;; 40-49 TEMPORARY FAILURE
+              [(and (>= status 40)
+                    (<= status 49))
+               (printf "status ~a: ~a\n" status
+                       (dict-ref temporary-failures status "temporary failure"))]
 
-      (iter url 5))))
+              ;; 50-59 PERMANENT FAILURE
+              [(and (>= status 50)
+                    (<= status 59))
+               (printf "status ~a: ~a\n" status
+                       (dict-ref permanent-failures status "permanent failure"))]
+
+              ;; 60-69 CERTIFICATE REQUIRED
+              [(and (>= status 60)
+                    (<= status 69))
+               (displayln "certificate handling not yet implemented")])))
+
+        (iter url 5))))