Re: In "C" mode, how do I turn off electric mode?

[Alan Mackenzie <acm@muc.de>]

Hi again, Bruce!

On Mon, 26 Nov 2007, Bruce Korb wrote:

> I know I probably seem cranky.  I am feeling cranky, after all.
> I mean, I've used this wonderful editor for over 20 years and
> it has been getting better all the time.  Until I loaded version 22.1
> that came with my SuSE installation.  I really do find it irritating
> that I have to go find and eyeball parse this stuff:

Being cranky's OK.  It means that you want things set up _right_, and 
aren't prepared to be palmed off with rubbish.  That's why a lot of 
people come to Emacs in the first place.

Trouble is, what the "Right Thing" and "rubbish" are vary enormously from 
hacker to hacker.  So it means you've got to put in some work to configure 
your own Emacs.  Sometimes, this can be quite a lot of work.  Let's get 
going!

>
>> ;; Safe local variables:

[...snip...]

> only to discover that there really does not seem to be any way
> to shut up this damn "hack-local-variables-confirm" junk.
> Except to rewrite the thing and have it do nothing.  What a pain.
> I mean, really!  It is not a good interface to force all competent
> users to say, "Mother, please may I?" every time some new variable
> is encountered.  As best I can tell from my ability meander around
> this stuff, there is no other way.  So, I surely hope you do not
> change the name of that procedure that I am about to replace.

I'd be a little more gentle on this.  The file local variables mechanism 
is powerful enough to run arbitrary code.  This means it's powerful enough 
for somebody to crack your machine's security just by giving you a source 
file and have you load it into Emacs.  This could include downloading a 
virus or Trojan Horse from some web site.  The "hack-l-v-confirm" 
thing is a precaution against this.  It's probably worth putting up 
with this irritation.

I'd also suggest that irritations don't add up, they multiply.  So, if you
get the other problems sorted out, the local variables thingy won't seem 
nearly as bad.  Of course like you suggest, you could code your way around 
it if you're confident enough about the source files you'll be visiting.

> And I would still like to be able to press the space bar and not
> have my comment reformatted:

It seems you've got Auto Fill mode enabled, somehow.  Check this by 
looking for the word "fill" in the mode line.  The purpose of this 
mode is _precisely_ to reformat stuff when you press the space bar. 
;-)  It's just that CC Mode restricts this reformatting to comments, by 
default, since it would be silly to fill executable code.

If you've got Auto Fill on for all buffers, you could switch it off for CC 
Mode by putting this into your .emacs:

     (defun bk-cc-setup ()
       (auto-fill-mode -1))
     (add-hook 'c-mode-common-hook 'bk-cc-setup)

The hooks in CC Mode are described in chapter "CC Hooks" of the CC Mode 
manual.  This manual was completely overhauled just before Emacs 22.1 
was released.  It's worth a read.  ;-)

[ .... ]

> Here is an example.  I pressed "enter" and "*" and got this:
>
>    /*=event  power_fail_received
>     * evt-sev:     debug
>     * evt-class:   debug
>     * display:     'received <evt_type> regarding <disk_id>'
>     *              ' from node <src_node>: <text_id>'
>     *
>     * arg:  enum-pfail_evt_type_name, evt_type
>     * arg:  enum-pfail_evt_type_desc, text_id
>     *
>     * arg:  tpd_u32, src_node
>     * arg:  tpd_u32, disk_id
>     * arg:  tpd_u32, tag_type   <===================
> *
>    =*/

OK, I'm guessing here that you pressed <enter> with point at the end of 
the line I've marked "<===========".  Just as a matter of interest, you 
can type M-j to do this.  (See the chapter "Filling and Breaking" in the 
CC Mode manual.)

> Normally, I would expect the star to be "electric" and line up.

So would I.  But you only get this effect when "electric mode" is enabled. 
Have a look at your mode line: electric mode is indicated by the 
"l" in "C/l".  Try toggling this on and off with C-c C-l, then try typing 
this "*" again.  This is all described in Chapter "Minor Modes" in the CC 
Mode manual.

If you got the above problem when electric mode was on, then you've found 
a bug.  If this is the case, then to fix it, I'll need precise details 
of your CC Mode configuration, so that I can reproduce the failure. 
Would you please type C-c C-b from your C buffer, then post here the 
information it displays.  Thanks in advance!

> But I am also trying to disable electric mode because there is
> simply too much magic involved.  So, okay, I had to press "tab",
> but it is still weird:
>
>
>     * arg:  tpd_u32, tag_type
>    *
>    =*/

Post your configuration (with C-c C-b and cut and paste, as described 
above), then the reason this happens should become clear.

> So, I move the cursor in front of the "*" character and press "space-bar":
>
>
>     * arg:  tpd_u32, tag_type
>
>    *=*/
>
> and the cursor remains on the this new star, but on the next line.
> There is some magical property somewhere.  What nonsense is this?

It looks like you've got some automatic filling function running, though I 
don't think it's just plain Auto Fill Mode.  Maybe it says on the 
mode line.  Could you check this out, please, and let us know?

Also, this filling happens because the "=" on your comment closing 
line prevents CC Mode recognising the "*" as a "comment prefix".  So Auto 
Fill Mode thinks it's just ordinary text, and it coalesces it with the 
line above.  I'm suprised it didn't become "* =*/", though.

The thing here is to tell CC Mode that your comment prefixes can have an 
"=" sign.  Put the following into your .emacs (instead of the bit above):

     (defun bk-cc-setup ()
       (auto-fill-mode -1)
       (setq c-comment-prefix-regexp
         '((pike-mode . "//+!?\\|\\**")
           (awk-mode . "#+")
           (other . "//+\\|=?\\**"))))
     (add-hook 'c-mode-common-hook 'bk-cc-setup)

[The critical bit is the "=?" on the "other" line.]

> "describe-key" says that "space-bar" is still bound to "insert-self",
> but that is obviously not true.  How can I do simple stuff without
> resorting to X-clip/paste, changing modes to edit comments, reverting
> my distribution to a back-rev emacs or just punting my favorite editor
> and using VI?  :(  This is really way too painful.

VI?  That would indeed be painful.  ;-)

-- 
Alan Mackenzie (Ittersbach, Germany).