Re: [h-e-w] Need help with lisp function and comint interaction

[Stephen Leake]

Robert Mecklenburg <address@hidden> writes:

> I've got this function which will execute a cvs query to determine the
> tags on a cvs controlled file and build a for loop to remove the cvs
> tags on the file.  The function is very useful when renaming cvs
> files.  Unfortunately, it "fails" for files with long tags lists
> (precisely those where it would be most useful).  The failure, I
> believe, is that it doesn't properly wait for the cvs process output
> to complete before searching for tags.  I'm having trouble getting that
> part right.  Any suggestions?

I've also written some elisp to interface with cvs. I don't use
comint; I use start-process directly, and use a "sentinel" to process
the output when cvs is done. Emacs ensures the wait is done properly.

Here's a snippet:

(defun cvs-run-process (global-args command command-args files &optional 
post-process run-directory)
  "Change to 'run-directory', run \"cvs global-args command
command-args files\", output to current buffer. command is a string;
global-args, command-args, files are lists of strings."
  (interactive) ; for testing
  ;; check for a pre-existing process
  (when cvs-process
    (when (memq (process-status cvs-process) '(run stop))
          (error "Can not run two cvs processes simultaneously.")))

  ;; don't let user modify user buffer until the sentinal runs
  (use-local-map cvs-running-mode-map)

  ; setup process buffer
  (save-excursion
    (set-buffer cvs-process-buffer)
    (setq cvs-post-process post-process)
    (erase-buffer))

  (let* ((args (append cvs-global-flags
                       (if cvs-cvsroot (list "-d" cvs-cvsroot))
                       global-args
                       (list command)
                       command-args
                       files))
         (process-connection-type nil) ; Tell start-process to use a pipe, not 
a pty.
         (default-directory (or run-directory default-directory)))
    (save-excursion
      (set-buffer cvs-process-buffer)
      (goto-char (point-min))
      (insert cvs-program " " (mapconcat 'concat args " ") "\n"))
    (let ((process (apply 'start-process "cvs" cvs-process-buffer cvs-program 
args)))
      (set-process-sentinel process 'cvs-sentinel)
      (setq cvs-process process)
      (setq mode-line-process ": run")
      (force-mode-line-update)) ) )

(defun cvs-sentinel (proc msg)
  "Sentinel for the cvs command process."
  (when (memq (process-status proc) '(signal exit))
    (set-buffer (process-buffer proc))
    ;; cvs-user-buffer now has the right buffer-local value

    (set-buffer cvs-user-buffer)
    (use-local-map cvs-mode-map)

    (if (eq (process-exit-status proc) 1) ; error
        (progn
          (setq mode-line-process ": error")
          (cvs-show-output)
          ;; if post process is one of the following, run it even for
          ;; error status, because conflicts (sometimes !) report
          ;; error status
          (set-buffer cvs-process-buffer) ; cvs-post-process is only defined in 
that buffer
          (if (or
                (eq cvs-post-process 'cvs-post-refresh)
                (eq cvs-post-process 'cvs-post-update-diff-commit)
                )
              (funcall cvs-post-process)))
      ;; not error
      (setq mode-line-process ": ready")
      (set-buffer cvs-process-buffer) ; cvs-post-process is only defined in 
that buffer
      (if cvs-post-process
          (funcall cvs-post-process)))

    ;; Since the buffer and mode line will show that the
    ;; process is dead, we can delete it now.
    (delete-process proc)) )

See http://users.erols.com/leakstan/Stephe/emacs/index.html for the
full source code; sal-cvs-mode.zip

-- 
-- Stephe