Re: org-scan-tags

From: Carsten Dominik <carsten.dominik@gmail.com>
To: Ilya Shlyakhter <ilya_shl@alum.mit.edu>
Cc: emacs-orgmode <emacs-orgmode@gnu.org>
Subject: Re: org-scan-tags
Date: Thu, 3 Feb 2011 06:32:19 +0100	[thread overview]
Message-ID: <6A0ECD8D-8BB6-4BD6-9EC3-E6F4B09D0288@gmail.com> (raw)
In-Reply-To: <AANLkTinghT-fKTLVR9Mz9a3hrXUNu-f-XW8GjU8-0H9p@mail.gmail.com>

On Sep 15, 2010, at 5:19 AM, Ilya Shlyakhter wrote:

> In org-scan-tags, if todo-only is t, would it be possible to speed
> things up by changingthe regexp go to just the lines with a TODO
> keyword?

I believe this may cause a problem.  The scanner needs to see at least
every parent node to be able to collect all inherited tags.
So I think that a tree like

* heading
** one :tag1:
*** TODO two :tag2:

would incorrectly miss out on :tag1:

- Carsten

> I.e. in
>
>  (let* ((re (concat "^" outline-regexp " *\\(\\<\\("
>                     (mapconcat 'regexp-quote org-todo-keywords-1 "\ 
> \|")
>                     (org-re
>                      "\\>\\)\\)? *\\(.*?\\)\\(:[[:alnum:]_@:]+:\\)? 
> [ \t]*$")))
>
> remove the first "?" if todo-only is t.   Also, regexp-opt might make
> a more efficient regexp than mapconcat with regexp-quote.
>
> Reason for request:  I'm writing an extension of org for setting &
> checking goals, and want to quickly find entries with headlines of the
> form
>    GOAL ....
> of which there may be relatively few in a large file.   So, stepping
> through all entries and then checking them for the GOAL keyword is
> very inefficient.
> It would be much faster if the regexp included the GOAL as a keyword.
>
> It would be good if the parameter todo-only could be a list of
> strings, and org-scan-tags would return only the headlines where the
> todo keyword is from this list.
> It could use regexp-opt to make an efficient regexp for this.
>
> There also seem to be other opportunities for speeding up
> org-scan-tags in this way: e.g. if the match string includes +mytag,
> the regexp for the headline could include this as well.
> Similarly for properties.  Maybe, org-make-tags-matcher could return a
> list of tags and properties that must appear in any matching entry.
>
> It would also help if the tags matcher expression could refer to text
> properties stored on the headline -- perhaps, with conditions such as
> :myprop=X  (i.e. same as for org properties, but property name must be
> a keyword).   It already does this for the 'org-category text
> property.
> Then one can e.g. mark entries representing unmet goals with text
> properties, and then use a regular org-tags-view to browse them in a
> sparsetree
> or an agenda.
>
> Thanks,
>
> ilya
>
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