Re: [RFC] [PATCH] Changes to Tag groups - allow nesting and regexps

["Gustav Wikström" <gustav@whil.se>]

Hi, see below

> >
> > * lisp/org-agenda.el (org-agenda-filter-make-matcher-tag-exp): Deal with
> >   the case when the user provided an empty string to filter or exclude
> >   rows from the agenda.
> 
> Please provide a reference to the discussion that lead to this patch.

The reference being the subject-line and date of the mail from sgeorgii?

> 
> >        (let* ((tag (substring x 1))
> > -	     (isregexp (and (equal "{" (substring tag 0 1))
> > +	     (isemptystring (string= "" tag))
> > +	     (isregexp (and (not isemptystring)
> > +			    (equal "{" (substring tag 0 1))
> >  			    (equal "}" (substring tag -1))))
> >  	     regexp)
> >  	(cond
> >  	 (isregexp
> >  	  (setq regexp (substring tag 1 -1))
> >  	  (setq f1 (list 'org-match-any-p regexp 'tags)))
> > +	 (isemptystring
> > +	  (setq f1 '(not tags)))
> >  	 (t
> >  	  (setq f1 (list 'member (downcase tag) 'tags))))
> >  	(when (eq op ?-)
> 
> Nitpick time:
> 
> You don't need isemptystring if it is the first branch in cond
> 
>   (cond
>    ((string= "" tag) (setq f1 '(not tags)))
>    (isregexp ...)
>    (t ...))
> 
> Obviously, in that case, you don't need to change isregexp at all.

Hmm, since the error was thrown when trying to look at indexes outside of the string in (substring ... ), I don't see how isregexp can be left as is. We have to make sure the substring-code is not evaluated if the tag is empty. What am I missing? 

> 
> 
> Regards,
> 
> --
> Nicolas Goaziou                                                0x80A93738