invoke command.function with completion value not string

this means a function that wants a buffer (for example) gets called
with the actual buffer not the buffer name

command.fnl

@@ -29,7 +29,7 @@
   [:url  #(doto {} (tset $1 $1)) #(do "http://www.example.com")]
   ]
  (fn [{:url url :buffer buffer}]
-   (let [b (Buffer.find buffer)] (: b :visit url))))
+   (buffer:visit url)))
 
 (fn find-command [name]
   (. commands name))
@@ -77,8 +77,10 @@
          })
 
       {:command c :this-param k :collected-params p}
-      (do
-        (tset p k input-string)
+      (let [{ : completer}  (. c.params k)
+            vals (completer input-string)
+            value (. vals input-string)]
+        (tset p k value)
         (state-for-next-param c p))
 
       {:command c :this-param nil :collected-params p}

dunlin.fnl

@@ -9,7 +9,7 @@
 ;;; when we decide how to do an init file/rc file, this will go in it
 
 (local my-keymap {
-                  "g" ["visit-location" {:buffer #(. (. $1 :buffer) :name)}]
+                  "g" ["visit-location" {:buffer #$1.buffer }]
                   "M-q" ["quit-browser" {}]
                   "C-x" {
                        "C-c" ["quit-browser" {}]