Re: Matching labels with buttons

[Stephen Berman]

On Mon, 15 Jul 2024 11:25:28 +0000 Heime <heimeborgia@protonmail.com> wrote:

> Sent with Proton Mail secure email.
>
> On Monday, July 15th, 2024 at 11:17 PM, Heime <heimeborgia@protonmail.com> 
> wrote:
>
>> I want to match cases such as
>>
>> Label [-]
>>
>> Have constructed the following regexp, but it does not match the above
>>
>> "\\(.\\)\\(\\s-\\[\\-\\]\\s-\\)"
>>
>> I aw using
>>
>> (when (string-match "\\(.\\)\\(\\s-\\[\\-\\]\\s-\\)" text)
>
> In the code I have
>
>   (if (string-match "\\(\\s-*\\[\\-\\]\\s-*\\)\\(.*\\)" label)    ; [-] LB
>
>       (progn
>         (setq bt (match-string 1 label))
>         (setq lb (match-string 2 label))
>         (setq result
>                (concat bt (propertize lb 'face '(:foreground "red")))))
>
>
>     (when (string-match "\\(.*\\)\\(\\s-*\\[\\-\\]\\s-*\\)" label) ; LB [-]
>
>       (setq lb (match-string 1 label))
>       (setq bt (match-string 2 label))
>       (setq result
>              (concat (propertize lb 'face '(:foreground "red")) bt)))
>
> Doing some tests with
>
> "OFF [-]"
>
> keeps matching the first string-match

That's because your regexp isn't anchored, so string-match succeeds if
it finds a match anywhere in the string passed to it.  To avoid this,
start the regexp with "\\`", which anchors it to the start of the string
being matched against; see (info "(elisp) Regexp Backslash").

Steve Berman