In reply to @asymmetric:matrix.dapp.org.uk
But the 80 column mark provides an upper bound for sentence length

I'm trying to make an extension that replaces the nix-repl language tag with the text language tag. By language tag I mean the first word after the triple backtick in fenced code blocks.

from docutils import nodes
from docutils.parsers.rst import directives
from sphinx.util.docutils import SphinxDirective

class Directive(SphinxDirective):
    has_content = True

    def run(self):
        content = '\n'.join(self.content)
        code_block = nodes.literal_block(classes=['nix-repl'], language='text')
        code_block.append(nodes.Text(content))
        return [code_block]

def setup(app):
    app.add_directive('nix-repl', Directive)

Because I really want to mark some fenced code blocks as nix-repl.

I wrote a program that parses the same sources, unrelated to sphinx, runs those nix repl examples in actual nix repl.

sphinx.ext.doctest is an extension which does something similar: https://github.com/sphinx-doc/sphinx/blob/0bad447070d45fc5538aed9bf15a1716c628f321/sphinx/ext/doctest.py#L157

https://www.sphinx-doc.org/en/master/usage/extensions/doctest.html#module-sphinx.ext.doctest

sphinx.ext.doctest is an extension which does something similar (but for Python): https://github.com/sphinx-doc/sphinx/blob/0bad447070d45fc5538aed9bf15a1716c628f321/sphinx/ext/doctest.py#L157

https://www.sphinx-doc.org/en/master/usage/extensions/doctest.html#module-sphinx.ext.doctest

In reply to @osslate:fsfe.org
In any case, you might get better support from the Sphinx chat channel unless we've resident Sphinx experts about