Add a prefix option to web app

web.lisp

@@ -36,6 +36,7 @@
 
 (defparameter *default-port* 8000)
 (defparameter *default-address* "127.0.0.1")
+(defparameter *default-prefix* "/")
 
 (defwidget truth-table ()
   ((data :initform nil
@@ -297,7 +298,11 @@ reblocks bug.")
     (#\p "port" port t
          ,(format nil "specify port to use (default: ~d)" *default-port*))
     (#\a "address" address t
-         ,(format nil "specify address to bind to (default: ~a)" *default-address*)))
+         ,(format nil "specify address to bind to (default: ~a)"
+                  *default-address*))
+    (#\x "prefix" prefix t
+         ,(format nil "specify the URL prefix (default: ~a)"
+                  *default-prefix*)))
   "Spec for use in `parse-command-line.")
 
 (defun determine-port (opts)
@@ -342,10 +347,14 @@ arguments."
                 (uiop:quit 0)))
           (when cmdline-error
             (uiop:quit 1))
+          (defapp truth-table-app
+            :prefix (or (option-value 'prefix opts)
+                        *default-prefix*))
           (reblocks/server:start :apps '(truth-table-app)
                                  :port port
                                  :interface address
-                                 :debug (option-value 'debug opts)))))))
+                                 :debug (option-value 'debug opts)
+                                 :disable-welcome-app t))))))
 
 (defun toplevel ()
   "Top-level function to be passed to `save-lisp-and-die'."