bug#6100: c-beginning-of-defun doesn't push mark

bug#6100: c-beginning-of-defun doesn't push mark

[Juri Linkov]

There is one annoying difference between `beginning-of-defun'
and `c-beginning-of-defun':

`beginning-of-defun' and `end-of-defun' pushes the mark for the
old point location to the mark ring with this code:

  (or (not (eq this-command 'beginning-of-defun))
      (eq last-command 'beginning-of-defun)
      (and transient-mark-mode mark-active)
      (push-mark))

but `c-beginning-of-defun' doesn't do that.

This patch add the same code to `c-beginning-of-defun' and `c-end-of-defun':

=== modified file 'lisp/progmodes/cc-cmds.el'
--- lisp/progmodes/cc-cmds.el	2010-04-19 15:07:52 +0000
+++ lisp/progmodes/cc-cmds.el	2010-05-04 16:01:05 +0000
@@ -1501,6 +1501,11 @@ (defun c-beginning-of-defun (&optional a
   (interactive "p")
   (or arg (setq arg 1))
 
+  (or (not (eq this-command 'c-beginning-of-defun))
+      (eq last-command 'c-beginning-of-defun)
+      (and transient-mark-mode mark-active)
+      (push-mark))
+
   (c-save-buffer-state
       (beginning-of-defun-function end-of-defun-function
        (start (point))
@@ -1604,6 +1609,11 @@ (defun c-end-of-defun (&optional arg)
   (interactive "p")
   (or arg (setq arg 1))
 
+  (or (not (eq this-command 'c-end-of-defun))
+      (eq last-command 'c-end-of-defun)
+      (and transient-mark-mode mark-active)
+      (push-mark))
+
   (c-save-buffer-state
       (beginning-of-defun-function end-of-defun-function
        (start (point))

-- 
Juri Linkov
http://www.jurta.org/emacs/

bug#6100: c-beginning-of-defun doesn't push mark

[Stefan Monnier]

> There is one annoying difference between `beginning-of-defun'
> and `c-beginning-of-defun':

> `beginning-of-defun' and `end-of-defun' pushes the mark for the
> old point location to the mark ring with this code:

>   (or (not (eq this-command 'beginning-of-defun))
>       (eq last-command 'beginning-of-defun)
>       (and transient-mark-mode mark-active)
>       (push-mark))

> but `c-beginning-of-defun' doesn't do that.

> This patch add the same code to `c-beginning-of-defun' and `c-end-of-defun':

Of course, I'd argue that the right fix is to use `beginning-of-defun'.


        Stefan

bug#6100: c-beginning-of-defun doesn't push mark

[Juri Linkov]

>> There is one annoying difference between `beginning-of-defun'
>> and `c-beginning-of-defun':
>
>> `beginning-of-defun' and `end-of-defun' pushes the mark for the
>> old point location to the mark ring with this code:
>
>>   (or (not (eq this-command 'beginning-of-defun))
>>       (eq last-command 'beginning-of-defun)
>>       (and transient-mark-mode mark-active)
>>       (push-mark))
>
>> but `c-beginning-of-defun' doesn't do that.
>
>> This patch add the same code to `c-beginning-of-defun' and `c-end-of-defun':
>
> Of course, I'd argue that the right fix is to use `beginning-of-defun'.

Do you mean cc-mode should use `beginning-of-defun-function'?

-- 
Juri Linkov
http://www.jurta.org/emacs/

bug#6100: c-beginning-of-defun doesn't push mark

[Stefan Monnier]

> Do you mean cc-mode should use `beginning-of-defun-function'?

AFAIK it already does, so just using the beginning-of-defun command
should DTRT.


        Stefan

bug#6100: c-beginning-of-defun doesn't push mark

[Alan Mackenzie]

Hi, Juri,

On Wed, May 05, 2010 at 09:28:32PM +0300, Juri Linkov wrote:
> >> There is one annoying difference between `beginning-of-defun'
> >> and `c-beginning-of-defun':

> >> `beginning-of-defun' and `end-of-defun' pushes the mark for the
> >> old point location to the mark ring with this code:

> >>   (or (not (eq this-command 'beginning-of-defun))
> >>       (eq last-command 'beginning-of-defun)
> >>       (and transient-mark-mode mark-active)
> >>       (push-mark))

> >> but `c-beginning-of-defun' doesn't do that.

> >> This patch add the same code to `c-beginning-of-defun' and `c-end-of-defun':

> > Of course, I'd argue that the right fix is to use `beginning-of-defun'.

> Do you mean cc-mode should use `beginning-of-defun-function'?

This would be OK.  Unfortunately, end-of-defun-function isn't called
cleanly.  With a C-M-e, {beginning,end}-of-defun-function are often
called 4 times.  c-end-of-defun, however, already does the Right Thing on
its own.

c-{beginning,end}-of-defun have a heavy overhead in determining the type
of starting position (inside the brace block, inside the function header,
etc.) and in locating a top-level brace (at the start) and the start of
the header (at the end).  This overhead dominates the speed of the
functions, which work essentially as fast regardless of how big ARG is.

The speed of c-{beginning,end}-of-defun have presented problems from time
to time.  Quadrupling CC Mode's end-of-defun's runtime doesn't seem a
good idea.  I want to keep the handling of c-{beginning,end}-of-defun
symmetrical for ease of maintenance.

I would favour your patch to these defuns which pushes the marks.

> Juri Linkov

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#6100: c-beginning-of-defun doesn't push mark

[Stefan Monnier]

> The speed of c-{beginning,end}-of-defun have presented problems from time
> to time.  Quadrupling CC Mode's end-of-defun's runtime doesn't seem a
> good idea.  I want to keep the handling of c-{beginning,end}-of-defun
> symmetrical for ease of maintenance.

IIUC the speed of those operations has been a problem when called many
times within a single command (i.e. the cumulative time became
a problem), so it shouldn't be a problem for interactive use where doing
it 4 times rather than 1 shouldn't be noticeable.

IOW, the problem was algorithmic, but running the same code 4 times
makes no difference algorithmically.

> I would favour your patch to these defuns which pushes the marks.

It's your code, so it's your choice.


        Stefan

bug#6100: c-beginning-of-defun doesn't push mark

[Alan Mackenzie]

Hi, Stefan and Juri,

On Tue, May 11, 2010 at 03:22:10PM -0400, Stefan Monnier wrote:

> > I would favour your patch to these defuns which pushes the marks.

> It's your code, so it's your choice.

I've commited Juri's patch.  The mark will now be pushed when
appropriate in c-{beginning,end}-of-function.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).

bug#6100: Fix

[Alan Mackenzie]

c-{beginning,end}-of-function now push the mark like beginning-of-defun
does.

-- 
Alan Mackenzie (Nuremberg, Germany).