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Re: Comint: handle raw tab
Re: Comint: handle raw tab
Tue, 13 Sep 2011 14:19:09 -0400
Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux)
>> IMO native tab completion for subprocess REPLs is a common enough need
>> that the basic machinery should be handled by Emacs itself, i.e.
>> probably the comint library. I'm somewhat surprised there is no such
>> code yet (or is there, outside Emacs perhaps?).
> I agree with the exposed above, many modern REPLs comint can interact with
> have TAB completion out of the box. We should use that when it's available
> instead of duplicating efforts.
I agree that would be good.
You can check the gdb completion code in gud.el for an example.
(defun gud-gdb-completions (context command)
"Completion table for GDB commands.
COMMAND is the prefix for which we seek completion.
CONTEXT is the text before COMMAND on the line."
(let* ((start (- (point) (field-beginning)))
(gud-gdb-run-command-fetch-lines (concat "complete " context command)
;; From string-match above.
;; `gud-gdb-run-command-fetch-lines' has some nasty side-effects on the
;; buffer (via `gud-delete-prompt-marker'): it removes the prompt and then
;; re-adds it later, thus messing up markers and overlays along the way.
;; This is a problem for completion-in-region which uses an overlay to
;; create a field.
;; So we restore completion-in-region's field if needed.
;; FIXME: change gud-gdb-run-command-fetch-lines so it doesn't modify the
;; buffer at all.
(when (/= start (- (point) (field-beginning)))
(dolist (ol (overlays-at (1- (point))))
(when (eq (overlay-get ol 'field) 'completion)
(move-overlay ol (- (point) start) (overlay-end ol)))))
;; Protect against old versions of GDB.
(string-match "^Undefined command: \"complete\"" (car complete-list))
(error "This version of GDB doesn't support the `complete' command"))
;; Sort the list like readline.
(setq complete-list (sort complete-list (function string-lessp)))
;; Remove duplicates.
(let ((first complete-list)
(second (cdr complete-list)))
(if (string-equal (car first) (car second))
(setcdr first (setq second (cdr second)))
(setq first second
second (cdr second)))))
;; Add a trailing single quote if there is a unique completion
;; and it contains an odd number of unquoted single quotes.
(and (= (length complete-list) 1)
(let ((str (car complete-list))
(while (string-match "\\([^'\\]\\|\\\\'\\)*'" str pos)
(setq count (1+ count)
pos (match-end 0)))
(and (= (mod count 2) 1)
(setq complete-list (list (concat str "'"))))))
(defun gud-gdb-completion-at-point ()
"Return the data to complete the GDB command before point."
(let ((end (point))
(skip-chars-backward "^ " (comint-line-beginning-position))
(list start end