Re: !(.pattern) can match . and .. if dotglob is enabled

[Chet Ramey]

On 6/5/21 8:42 PM, Nora Platiel wrote:

> > The "matched explicitly" refers to the previous sentence, which talks about
> > the `.' at the start of a filename or path component needing to be matched
> > explicitly by a pattern beginning with a `.' or containing a `.' at the
> > right spot (after a `/'). I can add language to clarify that.
>
> What about this?
> The character `.' at the start of the
> | filenames `.' and `..' must always be matched explicitly, even if dotglob
> | is set. 

I added something similar, with additional wording about a `.' at the start
of a pattern.


> Yes, it all depends on the "universal set" from which the matches of the inner 
> `pattern-list' are subtracted.
> But in the current implementation, the inner matches are subtracted from:
> - all files, if dotglob is set
> - all except dot files, if dotglob is unset
>
> The inclusion of `.' and `..' when dotglob is set, seems inconsistent with the 
> exclusion of dot files when dotglob is unset.
> I think it would be most intuitive and useful to define the universal set to be 
> whatever `*' can expand to.

I can see how this would be more intuitive. Let's try it. I'll put support
in the next devel branch push.


> About the behavior of the extended operators ?,*,+,@ (with my proposed changes 
> when dotglob is set), I'm not sure there's a need for explanation. I think it 
> comes natural if you mentally translate the extended pattern into a sequence of 
> non-extended patterns.
>
> About `!()', we could say:

I'm leaning towards a general statement about how dotglob affects the set
of filenames that are tested against the extended patterns, rather than
calling out `!' specially.

Chet

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/