Thank you for your answer, and sorry for the late reply

Ok I think I understood the mechanism, but I don't understand how to use this regular expression (the one given by, for example,
(org-tags-expand "GTD")
which gives me the regular expression "with the other tags"
)

I see perfectly the idea : a search is done with org-agenda with this regular expression. But I can't use it.

The problem is that I don't know how to use this regular expression with a function that returns the tags. Do you have any clue (piece of code where it is already used ? A function allowing me to translate this regular expression into a simple tag? Do I just have to convert this regular expression into a list of tags? Is it possible? I'm asking myself all these questions because I just don't know where to go ^^)

Thanks in advance for your future answer.

Le lun. 29 août 2022 à 13:57, Ihor Radchenko <yantar92@gmail.com> a écrit :

Cletip Cletip <clement020302@gmail.com> writes:

> Yes I understand both perfectly. I think some people (like me) would like
> to connect them, others would not want to bring them together.
> But how to get the hierarchy (or the families) used by org agenda with a
> function like "org-get-tags" ?

You will probably need to combine org-get-tags output with regexp
generated by org-tags-expand. Tag hierarchy in Org is a just a search
wrapper - no real tags are changed in the file; only the matching.

--
Ihor Radchenko,
Org mode contributor,
Learn more about Org mode at https://orgmode.org/.
Support Org development at https://liberapay.com/org-mode,
or support my work at https://liberapay.com/yantar92