The extension should not produce raw HTML but create Block and Image object about asciidoctor-plantuml

[hsanson]

Sounds interesting but I would require guidance since I do not know what you mean with Block and Image objects. Pointers to documentation or examples would be useful.

[ggrossetie]

Sure I will try to work on a pull request 👍
As far as I know, there's not much documentation but you can use utility methods available in an extension, for instance: https://github.com/asciidoctor/asciidoctor/blob/1cde78f91aca9b7c9ca542ad118f6a736a12c693/lib/asciidoctor/extensions.rb#L191

You can also take inspiration from Asciidoctor Diagram:

• create an image block: https://github.com/asciidoctor/asciidoctor-diagram/blob/ddb0db13b3e75901712d98911da96a203f6da8f1/lib/asciidoctor-diagram/diagram_processor.rb#L228

• create a literal block: https://github.com/asciidoctor/asciidoctor-diagram/blob/ddb0db13b3e75901712d98911da96a203f6da8f1/lib/asciidoctor-diagram/diagram_processor.rb#L263-L272