Re: [HELP] Fwd: Org format as a new standard source format for GNU manuals

[Ihor Radchenko <yantar92@gmail.com>]

Max Nikulin <manikulin@gmail.com> writes:

> On 01/10/2022 11:08, Ihor Radchenko wrote:
>> In particular, I suggest to (1) extend the existing special block elements
>> with Elisp-configurable :export settings; (2) add special block
>> equivalent object.
>
> While I do not mind to have flexible generic inline objects, I feel some 
> doubts.
>
> Export is already customizable through creation of derived backend. For 
> links :export property is merely an alternative way supposed to be more 
> convenient. In some sense it is a way to dispatch proper handler, a kind 
> of virtual function table, etc. I see a couple of limitations with link 
> export implementation.

Creating derived backend will force users to use that non-standard
backend for export - inconvenient. Especially for third-party backends.

:export property, among other things, can also provide a reasonable
fallback for arbitrary backend not considered in advance.

> 1. Interface is rather different from the derived backend property. 
> Instead of org-element object only selected properties (and backend 
> communication channel is available).

Is it? :export function for links is taking similar parameters with the
other export transcoders.

> 2. Unsure if there is a robust way to extend implementation of the 
> backend handler without replacing it completely. I mean a function that 
> modifies or sets some attributes and delegate real export to the default 
> handler.

We may provide something like :export-filter-object that will act
similar to `:filter-parse-tree' and replace the original link object
with arbitrary Org AST.

> Mentioned in this thread texinfo commands are not convincing reason for 
> special blocks from my point of view. They are different flavors of 
> verbatim (or code) object. If they are verbatim objects with some 
> additional property then they may be just exported by a backend that is 
> unaware of their kinds. It can be considered as graceful degradation. 
> For special blocks export handlers must be implemented for each backend 
> unless type hierarchy is someway declared.

No. There is no need to consider every possible backend. There could be
an export handler that will provide a fallback for unknown backend, if
needed.

> Earlier we discussed assigning attributes for inline objects. While 
> nesting is not involved, it may be a way to implement necessary texinfo 
> commands as verbatim with class or type attribute. I am unsure if 
> different types of special blocks is the best way to resolve nesting 
> problem. Verbatim custom objects require different rules of parsing.

Please do remember that texinfo commands, are _not_ verbatim. They can
contain other markup inside. I'd rather look at them as extended
emphasis. Their contents must be parsed as well.

> Actually I simplified things when wrote that a backend may be unaware of 
> verbatim type. When nesting is involved it should be ready at least to 
> nested verbatim object. E.g. markdown backend can not blindly wrap text 
> into backticks, it has to check if parent element is not a verbatim 
> snippet or a verbatim block.

Agree. See export filter idea.

-- 
Ihor Radchenko // yantar92,
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>