#+ATTR_MY-ASCII: in derived backend?

#+ATTR_MY-ASCII: in derived backend?

[Thorsten Jolitz]

Hi List, 

do derived backends set their attributes always via the 

,--------------
| +ATTR_BACKEND:
`--------------

construct of the parent backend and don't have their own 

,--------------
| +ATTR_MY-BACKEND:
`--------------

construct?

The following excerpt from the manual suggests this - and I actually
tried it out and the latter is not added as ':attr_my-backend "value"'
to the property list of the following element, but the former is added
as ':attr_backend "value"'.

,-----------------------------------------------------------------------------
| As an example, imagine we want the ascii back-end to display the
| language used in a source block, when it is available, but only when
| some attribute is non-nil, like the following:
|
|      #+ATTR_ASCII: :language t
|
| Because that back-end is lacking in that area, we are going to create a
| new back-end, my-ascii that will do the job.
|
|      (defun my-ascii-src-block (src-block contents info)
|        "Transcode a SRC-BLOCK element from Org to ASCII.
|      CONTENTS is nil.  INFO is a plist used as a communication
|      channel."
|        (if (not (org-export-read-attribute :attr_ascii src-block :language))
|          (org-export-with-backend 'ascii src-block contents info)
|        (concat
|         (format ",--[ %s ]--\n%s`----"
|                 (org-element-property :language src-block)
|                 (replace-regexp-in-string
|                  "^" "| "
|                  (org-element-normalize-string
|                   (org-export-format-code-default src-block info)))))))
|
|      (org-export-define-derived-backend 'my-ascii 'ascii
|        :translate-alist '((src-block . my-ascii-src-block)))
`-----------------------------------------------------------------------------

But OTOH, aren't things like 

,--------------
| +ATTR_BEAMER:
`--------------

working although its a derived backend? 

--
cheers,
Thorsten

Re: #+ATTR_MY-ASCII: in derived backend?

[Nicolas Goaziou]

Hello,

Thorsten Jolitz <tjolitz@gmail.com> writes:

> do derived backends set their attributes always via the 
>
> ,--------------
> | +ATTR_BACKEND:
> `--------------
>
> construct of the parent backend and don't have their own 
>
> ,--------------
> | +ATTR_MY-BACKEND:
> `--------------
>
> construct?

You can use any name you want for attributes

  #+attr_my-special-name

and then retrieve it with

  (org-export-read-attribute :attr_my-special-name element)


Regards,

-- 
Nicolas Goaziou

Re: #+ATTR_MY-ASCII: in derived backend?

[Thorsten Jolitz]

Nicolas Goaziou <n.goaziou@gmail.com> writes:

Hello,

> Thorsten Jolitz <tjolitz@gmail.com> writes:
>
>> do derived backends set their attributes always via the 
>>
>> ,--------------
>> | +ATTR_BACKEND:
>> `--------------
>>
>> construct of the parent backend and don't have their own 
>>
>> ,--------------
>> | +ATTR_MY-BACKEND:
>> `--------------
>>
>> construct?
>
> You can use any name you want for attributes
>
>   #+attr_my-special-name
>
> and then retrieve it with
>
>   (org-export-read-attribute :attr_my-special-name element)

I've seen this in ox backends, but since I sometimes simply use the
parse-tree as produced by `org-element-parse-buffer', I wonder why
something like 

,------------------------------------------------
| #+CAPTION: My minimal table
| #+ATTR_HTML: :border 2 :rules all :frame border
| | col1 | col2 |
| |------+------|
| | val1 | val2 |
`------------------------------------------------

actually is included in the tables property list

,--------------------------------------------------------------------------
| (table (begin 205... attr_html (":border 2 ... :frame border") ...) )
`--------------------------------------------------------------------------

although the exporter is never called - only org-element?


PS
I would like to have that too - how is that achieved?

-- 
cheers,
Thorsten