repexp to collapse multiple blank lines into one

repexp to collapse multiple blank lines into one

[B. T. Raven]

Is there a way to use M-C-% to flush extra blank lines from a buffer.
Something like:
Query replace regexp:  ^$+ [which of course doesn't work, presumably
because $ has to be last]
with:      C-j

I know about C-x C-o but that's interactive rather than batch mode.

Thanks,

Ed

Re: repexp to collapse multiple blank lines into one

[Friedrich Laher]

you could run until search fail replacing 2 newlines by one

B. T. Raven wrote:

>Is there a way to use M-C-% to flush extra blank lines from a buffer.
>Something like:
>Query replace regexp:  ^$+ [which of course doesn't work, presumably
>because $ has to be last]
>with:      C-j
>
>I know about C-x C-o but that's interactive rather than batch mode.
>
>Thanks,
>
>Ed
>
>
>_______________________________________________
>Help-gnu-emacs mailing list
>Help-gnu-emacs@gnu.org
>http://lists.gnu.org/mailman/listinfo/help-gnu-emacs
>
>  
>

Re: repexp to collapse multiple blank lines into one

[Peter Dyballa]

Am 09.10.2005 um 14:27 schrieb B. T. Raven:

> Query replace regexp:  ^$+ [which of course doesn't work, presumably
> because $ has to be last]
> with:      C-j
>

What about ^C-j+ with C-j?

--
Greetings

   Pete

A child of five could understand this!  Fetch me a child of five.

Re: repexp to collapse multiple blank lines into one

[Neon Absentius]

On Sun, Oct 09, 2005 at 12:27:07PM +0000, B. T. Raven wrote:
> Is there a way to use M-C-% to flush extra blank lines from a buffer.
> Something like:
> Query replace regexp:  ^$+ [which of course doesn't work, presumably
> because $ has to be last]
> with:      C-j
> 

The following seems to work

C-M-% \(^C-qC-j\)+ RET \1 RET

Provided of course that your lines are really blank and do not contain 
any spaces, tabs etc.
 
> Thanks,
> 
> Ed
> 

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov

Re: regexp to collapse multiple blank lines into one

[B. T. Raven]

"Neon Absentius" <absent@sdf.lonestar.org> wrote in message
news:mailman.10556.1128865819.20277.help-gnu-emacs@gnu.org...
> On Sun, Oct 09, 2005 at 12:27:07PM +0000, B. T. Raven wrote:
> > Is there a way to use M-C-% to flush extra blank lines from a
buffer.
> > Something like:
> > Query replace regexp:  ^$+ [which of course doesn't work, presumably
> > because $ has to be last]
> > with:      C-j
> >
>
> The following seems to work
>
> C-M-% \(^C-qC-j\)+ RET \1 RET
>
> Provided of course that your lines are really blank and do not contain
> any spaces, tabs etc.
>
> > Thanks,
> >
> > Ed
> >
>
> --
>  There is no national science just as there is no national
> multiplication table; what is national is no longer science.
>          -- Anton Checov

Thanks F.L., P.D., N.A. Neon's solution seems the easiest to me. I need
this only because I can't get control chars into the replacement string.
The replacement can be a bare RET but you can't replace with less than
nothing, i.e. replacing a regexp with nothing and then backspacing to
get rid of the blank line.  Could this be related to the fact that
C-<spacebar> is no longer bound to 'set-mark'? It used to be, but now
C-h k reports nothing, (in fact, doesn't react at all) to that keypress.

Ed, child of four.

Re: regexp to collapse multiple blank lines into one

[Kevin Rodgers]

B. T. Raven wrote:
 > "Neon Absentius" <absent@sdf.lonestar.org> wrote in message
 > news:mailman.10556.1128865819.20277.help-gnu-emacs@gnu.org...
 >>The following seems to work
 >>
 >>C-M-% \(^C-qC-j\)+ RET \1 RET
 >>
 >>Provided of course that your lines are really blank and do not contain
 >>any spaces, tabs etc.
 >
 > Thanks F.L., P.D., N.A. Neon's solution seems the easiest to me. I need
 > this only because I can't get control chars into the replacement string.
 > The replacement can be a bare RET but you can't replace with less than
 > nothing, i.e. replacing a regexp with nothing and then backspacing to
 > get rid of the blank line.

Why can't you use the same technique to put a control character into the
replacement string as Neon suggests for the search string/regexp
(namely, C-q)?

I'll admit, I don't understand why that solution works: it appears to
replace the matched sequence of LFD characters with itself, instead of
replacing it with just a single LFD character (or nothing at all,
depending on the desired result).

 > Could this be related to the fact that
 > C-<spacebar> is no longer bound to 'set-mark'? It used to be, but now
 > C-h k reports nothing, (in fact, doesn't react at all) to that keypress.

No.  When you type C-SPC, your terminal is no longer sending anything
for Emacs to interpret.  Try C-@ instead.

-- 
Kevin Rodgers

Re: regexp to collapse multiple blank lines into one

[Neon Absentius]

On Mon, Oct 10, 2005 at 10:35:01AM -0600, Kevin Rodgers wrote:
> B. T. Raven wrote:
> > "Neon Absentius" <absent@sdf.lonestar.org> wrote in message
> > news:mailman.10556.1128865819.20277.help-gnu-emacs@gnu.org...
> >>The following seems to work
> >>
> >>C-M-% \(^C-qC-j\)+ RET \1 RET
> >>
> >>Provided of course that your lines are really blank and do not contain
> >>any spaces, tabs etc.
> >
> > Thanks F.L., P.D., N.A. Neon's solution seems the easiest to me. I need
> > this only because I can't get control chars into the replacement string.
> > The replacement can be a bare RET but you can't replace with less than
> > nothing, i.e. replacing a regexp with nothing and then backspacing to
> > get rid of the blank line.
> 
> Why can't you use the same technique to put a control character into the
> replacement string as Neon suggests for the search string/regexp
> (namely, C-q)?
> 

Actually that also works.  The reason I used "\1" is that I had
already grouped the regexp so it saved me typing.

> I'll admit, I don't understand why that solution works: it appears to
> replace the matched sequence of LFD characters with itself, instead of
> replacing it with just a single LFD character (or nothing at all,
> depending on the desired result).
> 

I don't understand what you don't understand :) My solutions replaces
one or more occurences of a regexp with a single occurence.  Perhaps
you are worried abour efficiency? that if there is a single occurence
I replace it with itself?  In that case you are right.  A better
solution would be better:

C-M-% \(^C-qC-j\)\{2,\} RET \1 RET

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov

Re: regexp to collapse multiple blank lines into one

[Kevin Rodgers]

Neon Absentius wrote:
 > Actually that also works.  The reason I used "\1" is that I had
 > already grouped the regexp so it saved me typing.
...
 > I don't understand what you don't understand :) My solutions replaces
 > one or more occurences of a regexp with a single occurence.  Perhaps
 > you are worried abour efficiency?

No, it was just that I read \(...\)+ as \(...+\).

\(...\)+ is suspect to me, since in the general case ... can match
different literal strings in the buffer and it wasn't obvious to me what
\1 should refer to.  I know see that the Emacs manual says

      If a particular `\( ... \)' construct matches more than once
      (which can easily happen if it is followed by `*'), only the last
      match is recorded.

but I guess I was effected by my experience with a proprietary text
processing language (which shall remain nameless) that prohibited such
references.

In any case, replacing \(^ C-q C-j \)+ with \1 is 10 key strokes, which
is actually more typing than if you were to replace ^ C-q C-j + with C-q
C-j (6 keys).

-- 
Kevin Rodgers

Re: regexp to collapse multiple blank lines into one

[Neon Absentius]

On Mon, Oct 10, 2005 at 12:33:50PM -0600, Kevin Rodgers wrote:

> 
> In any case, replacing \(^ C-q C-j \)+ with \1 is 10 key strokes, which
> is actually more typing than if you were to replace ^ C-q C-j + with C-q
> C-j (6 keys).
> 

Yes indeed.  I didn't think of it.  I just wrote the first think
that came to my mind and it worked.  About the keystrokes though I
think that C-q shoud count for more than 1 keystroke; perhaps not 2
keystrokes but 1.5 so your solution has really 8 keystrokes :).
Still my solution is not that bad because it is general: a simple
modification of it will work whenever one whishes to replace
multiple occurences of a regexp with a single occurence.

Also on most files using ^ C-q C-j \{2,\} will save you a lot a
keystrokes because one won't have to press all these "y".

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov

Re: regexp to collapse multiple blank lines into one

[Tim X]

Neon Absentius <absent@sdf.lonestar.org> writes:

> On Mon, Oct 10, 2005 at 12:33:50PM -0600, Kevin Rodgers wrote:
> 
> > 
> > In any case, replacing \(^ C-q C-j \)+ with \1 is 10 key strokes, which
> > is actually more typing than if you were to replace ^ C-q C-j + with C-q
> > C-j (6 keys).
> > 
> 
> Yes indeed.  I didn't think of it.  I just wrote the first think
> that came to my mind and it worked.  About the keystrokes though I
> think that C-q shoud count for more than 1 keystroke; perhaps not 2
> keystrokes but 1.5 so your solution has really 8 keystrokes :).

So, in that case, is A 1.5 keystrokes while a is only 1?

Tim


-- 
Tim Cross
The e-mail address on this message is FALSE (obviously!). My real e-mail is
to a company in Australia called rapttech and my login is tcross - if you 
really need to send mail, you should be able to work it out!

Re: regexp to collapse multiple blank lines into one

[Neon Absentius]

On Wed, Oct 12, 2005 at 08:21:29AM +1000, Tim X wrote:
> Neon Absentius <absent@sdf.lonestar.org> writes:
> 
> > On Mon, Oct 10, 2005 at 12:33:50PM -0600, Kevin Rodgers wrote:
> > 
> > > 
> > > In any case, replacing \(^ C-q C-j \)+ with \1 is 10 key strokes, which
> > > is actually more typing than if you were to replace ^ C-q C-j + with C-q
> > > C-j (6 keys).
> > > 
> > 
> > Yes indeed.  I didn't think of it.  I just wrote the first think
> > that came to my mind and it worked.  About the keystrokes though I
> > think that C-q shoud count for more than 1 keystroke; perhaps not 2
> > keystrokes but 1.5 so your solution has really 8 keystrokes :).
> 
> So, in that case, is A 1.5 keystrokes while a is only 1?
> 

Yes.  Or maybe 1.3 since A is somewhat easier to type than C-a ;)

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov

Re: regexp to collapse multiple blank lines into one

[Peter Dyballa]

Am 10.10.2005 um 18:35 schrieb Kevin Rodgers:

> >>C-M-% \(^C-qC-j\)+ RET \1 RET
> >>
> I'll admit, I don't understand why that solution works: it appears to
>

But it's so easy: it's exactly one newline between the parentheses! 
Outside is the plus. So up to many occurences of newline get replaced 
by exactly one.

--
Greetings

   Pete

War springs from unseen and generally insignificant causes.
-Anonymous

Re: repexp to collapse multiple blank lines into one

[David Hansen]

On Sun, 09 Oct 2005 12:27:07 GMT B. T. Raven wrote:

[...]

And i thought he wrote his novels on a rusty typewriter... ;-)

David

Re: repexp to collapse multiple blank lines into one

[Neon Absentius]

On Mon, Oct 10, 2005 at 10:59:53PM +0200, David Hansen wrote:
> On Sun, 09 Oct 2005 12:27:07 GMT B. T. Raven wrote:
> 
> [...]
> 
> And i thought he wrote his novels on a rusty typewriter... ;-)

Well, Emacs has a long and rich history!

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov