Re: [External] : Use the characters "+" and "-" in regular expressions

[steve-humphreys]

This is a string of blanks, a string composed of whitespace of any length.

"                     "



> Sent: Thursday, May 20, 2021 at 10:50 PM
> From: tomas@tuxteam.de
> To: steve-humphreys@gmx.com
> Cc: "help-gnu-emacs@gnu.org" <help-gnu-emacs@gnu.org>
> Subject: Re: [External] :  Use the characters "+" and "-" in regular 
> expressions
>
> On Thu, May 20, 2021 at 12:37:17PM +0200, steve-humphreys@gmx.com wrote:
>
> [...]
>
> > Done some tests and got some strange results that thought would not match.  
> > Then things
> > made more sense after your clarification because when I looked at some of 
> > the strings,
> > there was a comma in them.
>
> OK. Glad I could help.
>
> > Am seeing how to match strings of blank lines
>
> What is "a string of blank lines"?
>
> I know strings of characters. But a line is not a character.
>
> Do you mean "several blank lines next to each other"? I don't
> think so. But what do you mean?
>
> > But " +" does not do the job.
>
> Again: you know by now that this will match "one or more spaces". Is
> that for you a "string of blanks" (huh: where did you leave the
> "line" from above?) or not?
>
> >                  I know why, but how can one match strings of blanks?
>
> To even have a chance to do that, you'll have to get hold of a more
> or less precise idea of what "a string of blanks" is. This is work.
>
> Begin with:
>
>   (string-match " +" "A summer full of butterflies")
>   => 1
>
> Bingo: the first run of one-or-more spaces is at the position 1
> (the first position in the string is 0, the "A"). So it's working
> as it should.
>
> So what is /your/ idea of "a string of blank lines" or "a string
> of blanks"? Only you can find out.
>
> If you feel you are stuck in that task, it sometimes help to collect
> a couple of examples and counter-examples (they'll come in handy
> when you try to test your attempts).
>
> Cheers
>  - t
>