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

[Jean Louis]

* steve-humphreys@gmx.com <steve-humphreys@gmx.com> [2021-05-20 17:28]:
> I have settled with
> 
>   (string-match "^[:blank:]*$" s)
> 
> This would match only strings with spaces, not sentences with
> spaces.  What do you think?

That one is good to match nothing:

(string-match "^[:blank:]*$" "") ⇒ 0

(string-match "^[:blank:]*$" " ") ⇒ nil

(string-match "^[:blank:]*$" "  ") ⇒ nil

You have to read the manual: (info "(elisp) Regular Expressions")

-- 
Jean

Take action in Free Software Foundation campaigns:
https://www.fsf.org/campaigns

Sign an open letter in support of Richard M. Stallman
https://stallmansupport.org/
https://rms-support-letter.github.io/