Re: [O] Parser - which values are possible for `archivedp'?

[Thorsten Jolitz]

Jonathan Leech-Pepin <address@hidden> writes:

> Hello,
>
> On 4 March 2014 09:47, Thorsten Jolitz <address@hidden> wrote:
>
>     
>     Nick Dokos <address@hidden> writes:
>     
>     > Thorsten Jolitz <address@hidden> writes:
>     >
>     >> Hi List,
>     >>
>     >> the name of headline attribute `archivedp' suggests its just a
>     boolean
>     >> nil/t variable, but in parse trees I see e.g. a list as value
>     >>
>     >> ,-----------------------
>     >> | :archivedp ("ARCHIVE")
>     >> `-----------------------
>     >>
>     >> and I vaguely remember that I have seen different symbols as
>     values of
>     >> this attribute too.
>     >>
>     >> So what do I have to expect as values here? A list of strings
>     or nil? Or
>     >> something else too? Whatever is defined in
>     >>
>     >> ,---------------------------------------------------
>     >> | org-archive-tag is a variable defined in `org.el'.
>     >> | Its value is "ARCHIVE"
>     >> `---------------------------------------------------
>     >>
>     >> ?
>     >>
>     >> PS
>     >>
>     >> If the tag is just a string like in this case, why is it shown
>     as
>     >> list in the parse tree?
>     >
>     > It is set like this
>     > (let
>     > ...
>     > (archivedp (member org-archive-tag tags))
>     > ...)
>     >
>     > in org-element.el. It is effectively a boolean, but there is no
>     > need to reduce the return value of ``member'' to t if it is
>     non-nil:
>     >
>     > ,----
>     > | member is a built-in function in `C source code'.
>     > |
>     > | (member ELT LIST)
>     > |
>     > | Return non-nil if ELT is an element of LIST. Comparison done
>     with
>     > | equal'.
>     > `----
>     >
>     > So if non-nil, it will be a list of tags, starting with the
>     value of
>     > org-archive-tag. AFAICT, the rest of the tags can be arbitrary.
>     
>     
>     
>     ** Second Level 2 :tag:my:ARCHIVE:
>     
>     
>     ,------------------------------------------------
>     | :tags ("tag" "my") [...] :archivedp ("ARCHIVE")
>     `------------------------------------------------
>
> Change the order of the tags so that Archive comes before the others
> and you get:
>
> ** Second level 2 :ARCHIVE:tag:my:
> :tags ("tag" "my") :archivedp ("ARCHIVE" "tag" "my")

A very useful feature of the `member' function in lisp programming, but
not that great in this case I would say ... why not use (car (member ...))?
Then its just a string, and the single value of interest.

-- 
cheers,
Thorsten