Re: [O] [PATCH]Extend export hook example for removing headlines with tag ignore_heading

[Rasmus]

Ondřej Grover <address@hidden> writes:

> I have no idea how to get around this. It stems from the basic problem in
> Org mode that there are no entry closures AFAIK: To export the "export" it
> would have to be under a heading that does not have the :noexport: tag.
> This is actually one of the reasons why ignoreheading is used in many
> cases, to separate entries without creating a real headline.

This is the format.  Comparing to org-inlinetasks, I prefer the standard
way.  I put my noexport headings in the end of the document.

>> If this is often needed feature, ox.el and potentially backends should be
>> patched to support it.  I think it would be great if ox did support it.
>> Of course, Nicolas would have the final say in such a matter.
>>
> I'm ok with that too, but it should be easily accessible so that people
> don't end up using broken snippets from the Internet.
> Therefore, such exporting functionality (I think it's mostly backend
> agnostic) would have to be well documented in the manual.

Patches welcome.  Note it's a difficult tasks and you should read up on
previous discussions of this topic beforehand.

>> But I'm not sure so difficult hacks should be promoted in the manual.
>>
> It would indeed be better if the user only enabled some option documented
> in the manual instead of using code snippets.

It's perfectly fine to use filters and hooks.  I have 12 in my latex
configuration alone.  But it's hacks.  The manual should not promote
hacks.

Org-hacks on Worg already has a section on ignoreheading, though it should
be updated to mention the solution in ox-extra.el.

> I think it's still reasonably simple and clear for an example. It shows
> many useful things.

But it lacks correctness.  Why not solve a simpler problem that can be
solved correctly?

> +Two hooks are run during the first steps of the export process.  The
> +first one, @code{org-export-before-processing-hook} is called before
Missing comma:                                        ,

> +expanding macros, Babel code and include keywords in the buffer.  The
> +second one, @code{org-export-before-parsing-hook}, as its name suggests,
"as its name suggests," is unnecessary.
> +happens just before parsing the buffer.  Their main use is for heavy
> +duties, that is duties involving structural modifications of the
> +document.

The first part of the sentence is unnecessary. 

> For example, one may want to remove every headline with the
> address@hidden tag (excluding those with the @samp{noexport} tag)
> +in the buffer and promote their children during export.  The following

See above.

>  @lisp
>  @group
> -(defun my-headline-removal (backend)
> -  "Remove all headlines in the current buffer.
> +(defun ignored-headlines-removal (backend)
> +  "Remove all headlines with the ignore_headline tag in the current buffer

The first line should be a complete sentence, and it's too long here.

> +and promote all child headlines underneath them.
>  BACKEND is the export back-end being used, as a symbol."
>    (org-map-entries
> -   (lambda () (delete-region (point) (progn (forward-line) (point))))))
> +   (lambda () (progn (org-map-tree (lambda () (when (> (outline-level) 1)
> +                                             (org-promote))))
> +                  (delete-region (point) (point-at-eol))))
> +   "+ignore_heading-noexport"))
>

progn is unneeded.

> +The second argument to the @code{org-map-entries} function is an
> +agenda-style match query string (@pxref{Matching tags and properties}).

Fine.

> +Note the underscore in the tag, it is not recommended to use the
> address@hidden tag because the Beamer export backend treates it in
> +a similar, yet more complicated way.  It may also be useful to exclude
> +the @samp{ignore_heading} tag from inheritance (@pxref{Tag
> +inheritance}).  Also note that functions used in these hooks require a
> +mandatory argument, a symbol representing the back-end used.

This promotes poor usage patterns IMO cf. above.

—Rasmus

-- 
This is the kind of tedious nonsense up with which I will not put