Re: Is it obvious that string-match syntax matching is affected by the current buffer?

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

On 13.03.2016 17:31, Tom wrote:
> I did a word constituent match with string-match and a question
> occured to me: what controls what is considered word constituent
> in this case?
>
> I checked info, but I saw no mention of this, so I did a test and
> yes, the current syntax table affects string-match:
>
> (let ((tab (make-syntax-table)))
>    (modify-syntax-entry ?a " " tab)
>    (with-syntax-table tab
>      (string-match "\\s-" "a")))
>
>
> Isn't a strange? E.g. I'm doing a string match in elisp, so I'm
> not working with the current buffer, yet its active syntax table
> affects the result of string-match. Seems to me these are
> different domains and string-match should have its own
> string-match-syntax-table or something, so there can be no
> match side effects depending on the currently active buffer.
>
> Do you think it's obvious for the elisp users that string-match
> is affected by the current buffer? Maybe the documentation should
> mention this. (Maybe it does, but I didn't see it.)
>
>
>

string-match here is called from inside a let, so the settings there 
prevail.
Also from inside let: "with-syntax-table tab" - whilst"tab" is also 
let-bound.

Let protects against outer settings, so current-buffer or not seems not 
at stake.