Re: [O] Custom export backend based on HTML: how to implement own blocks?

[Charles Berry]

Marcin Borkowski <mbork <at> wmi.amu.edu.pl> writes:

> 
> Hello,
> 
> I'd like to (ab)use the "underline" syntax for something else.
> Basically, I'd like to translate
> 
> _underlined_
> 
> to
> 
> <span class="my-own"><variant>underlined<variant></span>
> 
> and
> 
> _underlined|with variant_
> 
> to
> 
> <span class="my own"><variant>underlined</variant><variant>with
> variant</variant></span>
> 
> but only if the underlining is between
> 
> #+BEGIN_MYBLOCK
> ...
> #+END_MYBLOCK
> 
> How to achieve this?  In particular, I'd like to know:
> 
> 1. How can I know (in org-html-underline, for instance) whether I am in
> a MYBLOCK or not?
> 

You do not need to know this directly. See below:

> 2. How do I best translate the "|" syntax into "variants"?  More
> specifically: is it a good idea to do it in org-my-html-underline, by
> analysing the "underlined" text (as a string) or maybe it's better to
> write a filter?  (I guess the former idea is better.)
> 

Define two derived backends:

backend 1)  Use 'html as the parent. Add 'MYBLOCK' to the `:export-block'
list and define your own `org-backend1-export-block' transcoder with a fallback
to the parent backend for HTML blocks.

You will have access to the :value of MYBLOCK as a string. You can use 
`org-export-string-as' to process that value according to an arbitrary backend -
in this case you use `backend2'.

backend 2) Use html as the parent of this backend and define
 `org-backend2-underline' to use the rules you outline above. You can 
parse the `contents' arg for the `|' etc.

There might be a case for making `backend2' anonymous since you only replace 
one transcoder of the parent. There is an example in 
` org-html--format-toc-headline'.

HTH,

Chuck