Re: address@hidden: momentary-string-display input passing]

[Matthew Mundell]

Richard Stallman <address@hidden> writes:

> This change looks basically reasonable to me, except I don't think
> that an error is the right thing to do when the user types a function
> key or clicks the mouse instead of typing the specified key.  I think
> those should just be ignored, the way other input characters are
> ignored.
>
> Would someone like to make that change and install this?

The change does ignore such errors.  They are caught by the
condition-case around read-char.  A stray string in the condition case
handler's body makes the handler look like a call to error.  It may be
that I left the string there when turning an older call to error into
the condition case.

A new patch and a change log are below.

> From: Matthew Mundell <address@hidden>
> Subject: momentary-string-display input passing
> To: emacs-pretest-bug <address@hidden>
> Date: 17 Feb 2004 23:15:12 +0000
>
> The CVS Elisp manual has the following example for
> momentary-string-display.
>
> (momentary-string-display
>  "**** Important Message! ****"
>  (point) ?\r
>  "Type RET when done reading")
>
> The idea seems to be that an Enter in response will only remove the
> message.  However, evaluating the form (in the CVS Emacs) and pressing
> Enter in response also results in the insertion of a newline.
>
> The Enter key press is read with `read-event', which returns the
> symbol `return', which is different from ?\r.
>
> Perhaps the following change to momentary-string-display will be of
> help.  It uses read-char when the parameter to be matched, EXIT-CHAR,
> is a character.  It would need additions to handle mouse events.
>
> ===================================================================
> RCS file: /cvsroot/emacs/emacs/lisp/subr.el,v
> retrieving revision 1.379
> diff -c -r1.379 subr.el
> *** subr.el   16 Feb 2004 19:40:07 -0000      1.379
> - --- subr.el 17 Feb 2004 18:34:04 -0000
> ***************
> *** 1455,1463 ****
>                 (recenter 0))))
>         (message (or message "Type %s to continue editing.")
>                  (single-key-description exit-char))
> !       (let ((char (read-event)))
> !         (or (eq char exit-char)
> !             (setq unread-command-events (list char)))))
>         (if insert-end
>         (save-excursion
>           (delete-region pos insert-end)))
> - --- 1455,1475 ----
>                 (recenter 0))))
>         (message (or message "Type %s to continue editing.")
>                  (single-key-description exit-char))
> !       (let (char)
> !         (if (integerp exit-char)
> !             (condition-case nil
> !                 (progn
> !                   (setq char (read-char))
> !                   (or (eq char exit-char)
> !                       (setq unread-command-events (list char))))
> !               (error "Non-character input-event"
> !                      ;; character type exit-char will differ from this event
> !                      (setq unread-command-events (list char))))
> !           ;; assume exit-char an event
> !           (setq char (read-event))
> !           (or (eq char exit-char)
> !               (eq char (event-convert-list exit-char))
> !               (setq unread-command-events (list char))))))
>         (if insert-end
>         (save-excursion
>           (delete-region pos insert-end)))
>

2004-03-26  Matthew Mundell  <address@hidden>

        * subr.el (momentary-string-display): If EXIT-CHAR is a character
        then read input using read-char, catching any error resulting from
        the input of an event.  Otherwise read with read-event, comparing
        EXIT-CHAR to the input both as a character and an event
        description list.  Doc updated to match.


===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/subr.el,v
diff -u -r1.379 subr.el
--- lisp/subr.el        16 Feb 2004 19:40:07 -0000      1.379
+++ lisp/subr.el        26 Mar 2004 17:08:41 -0000
@@ -1423,9 +1423,11 @@

 (defun momentary-string-display (string pos &optional exit-char message)
   "Momentarily display STRING in the buffer at POS.
-Display remains until next character is typed.
-If the char is EXIT-CHAR (optional third arg, default is SPC) it is swallowed;
-otherwise it is then available as input (as a command if nothing else).
+Display remains until next event is input.
+Optional third arg EXIT-CHAR can be a character, event or event
+description list.  EXIT-CHAR defaults to SPC.  If the input is
+EXIT-CHAR it is swallowed; otherwise it is then available as
+input (as a command if nothing else).
 Display MESSAGE (optional fourth arg) in the echo area.
 If MESSAGE is nil, instructions to type EXIT-CHAR are displayed there."
   (or exit-char (setq exit-char ?\ ))
@@ -1455,9 +1457,23 @@
                  (recenter 0))))
          (message (or message "Type %s to continue editing.")
                   (single-key-description exit-char))
-         (let ((char (read-event)))
-           (or (eq char exit-char)
-               (setq unread-command-events (list char)))))
+         (let (char)
+           (if (integerp exit-char)
+               (condition-case nil
+                   (progn
+                     (setq char (read-char))
+                     (or (eq char exit-char)
+                         (setq unread-command-events (list char))))
+                 (error
+                  ;; `exit-char' is a character, hence it differs
+                  ;; from char, which is an event.
+                  (setq unread-command-events (list char))))
+             ;; `exit-char' can be an event, or an event description
+             ;; list.
+             (setq char (read-event))
+             (or (eq char exit-char)
+                 (eq char (event-convert-list exit-char))
+                 (setq unread-command-events (list char))))))
       (if insert-end
          (save-excursion
            (delete-region pos insert-end)))