Re: \W excludes underscore

On Tue, May 7, 2019 at 4:36 PM Erwin Brandstetter <brsaweda(at)gmail(dot)com>
wrote:

>
> https://www.postgresql.org/docs/current/functions-matching.html#POSIX-CLASS-SHORTHAND-ESCAPES-TABLE
> Table 9.19. Regular Expression Class-shorthand Escape:
>
> > \w [[:alnum:]_] (note underscore is included)
> > ...
> > \W [^[:alnum:]_] (note underscore is included)
>
> This is misleading as \w *includes* underscore, but \W *excludes* it. I
> suggest:
>

Its saying that the underscore is one of the characters that is included in
the exclusion, alongside the alphabetical characters.

> \w [[:alnum:]_] (underscore is included)
> ...
> \W [^[:alnum:]_] (underscore is excluded)
>
>
Or just "note the underscore"

The reader is already assumed to know that the capital letters and the
leading ^ in the bracket denote exclusion since its doesn't call out that
specifically.

David J.