better completion in emacs mode

Ignore-this: f6e41bcae10c422366b72296e6040086

darcs-hash:20110731163946-c41ad-1b75259fd6523bf3e06f39a9b716a3a0b86a93f5

src/uTop_emacs.ml

@@ -136,9 +136,16 @@ and process prompt buffer length command argument =
     | "complete" ->
         let input = read_data ~final_newline:false () in
         let start, words = UTop_complete.complete input in
+        let words = List.map fst words in
+        let prefix = LTerm_read_line.common_prefix words in
+        let index = String.length input - start in
+        let suffix = String.sub prefix index (String.length prefix - index) in
+        if suffix = "" then begin
           send "completion-start" "";
-        List.iter (fun (word, suffix) -> send "completion" word) words;
+          List.iter (fun word -> send "completion" word) words;
           send "completion-stop" "";
+        end else
+          send "completion-word" suffix;
         loop prompt buffer length
     | command ->
         Printf.ksprintf (send "stderr") "unrecognized command %S!" command;

src/utop.el

@@ -236,6 +236,9 @@ non-sticky mode."
       (setq utop-history-next nil)
       ;; Insert the last prompt
       (utop-insert-prompt utop-last-prompt))
+     ;; Complete with a word
+     ((string= command "completion-word")
+      (insert argument))
      ;; Start of completion
      ((string= command "completion-start")
       (setq utop-completion nil))