How to prepare an article for the Habr sandbox in an external markup file?

Question

Habr

Tell me, is there a mechanism in Habr's publishing system for importing an article for a sandbox from an external file?
Or can this be done only through manual insertion into the editor's form?
I want to prepare an article on programming in free syntax (FSP), using the methods of this very FSP.
According to the technology, one (++) text file of mixed code + description is fed to the input of the language system (see literary programming) , the output is the same file on which chains of text autoreplacement for calculated expressions are applied .
Accordingly, it would be nice to have a separate (from the habr article editor) way to preview such an article online or offline (check the correctness of tags, links, ..), and then upload the resulting local file to the habr editor for final verification and publication.

Answer 1

habrahabr.ru/company/tm/blog/262653
There is about converters
habr.caravus.org