Unable to render custom math output

[bitstein]

I am trying to make a custom renderer for the dollarmath plugin, because I need the output to have different classes than what the plugin provides.

class CustomMathRenderer(RendererHTML):
    def render_inline_math(self, tokens, idx, options, env):
        return f"<span class='language-math math-inline'>{tokens[idx].content}</span>"

    def render_math_block(self, tokens, idx, options, env):
        # Customize how math blocks are rendered
        return f"<div class='language-math math-block'>{tokens[idx].content}</div>"

I then have:

md = (
    MarkdownIt(
        "commonmark",
        {"breaks": False, "html": True},
        renderer_cls=CustomMathRenderer,
    )
    .use(front_matter_plugin)
    .use(footnote_plugin)
    .use(deflist_plugin)
    .use(dollarmath_plugin)
)

If I run md.parse, I can see math_inline printed. However, on running md.render, I do not see the custom rendering.

>>> tokens = md.parse(text)
>>> for token in tokens:
...     print(token.type)
...     if token.children:
...         for child in token.children:
...             print(child.type)
... 
paragraph_open
inline
text
math_inline
text
paragraph_close
>>> md.render(text)
'<p>Here is an inline math equation: <span class="math inline">E = mc^2</span>.</p>\n'

What am I doing wrong? Thank you!

[bitstein]

It dawned on me that render_math_inline and render_math_block were inside of a function and thus were not going to get overridden that way. I instead just wrote two functions:

def render_math_inline(
    self: RendererProtocol,
    tokens: Sequence[Token],
    idx: int,
    options: OptionsDict,
    env: EnvType,
):
    return f"<span class='language-math math-inline'>{tokens[idx].content}</span>"


def render_math_block(
    self: RendererProtocol,
    tokens: Sequence[Token],
    idx: int,
    options: OptionsDict,
    env: EnvType,
) -> str:
    return f'<div class="language-math math-display">\n{tokens[idx].content}\n</div>\n'

And then explicitly added them as render rules:

md = (
   MarkdownIt("commonmark", {"breaks": False, "html": True})
   .use(front_matter_plugin)
   .use(footnote_plugin)
   .use(deflist_plugin)
   .use(dollarmath_plugin)
)

md.add_render_rule("math_inline", render_math_inline)
md.add_render_rule("math_block", render_math_block)

Now it outputs correctly:

>>> text = "Here is an inline math equation: $E = mc^2$."
>>> md.render(text)
"<p>Here is an inline math equation: <span class='language-math math-inline'>E = mc^2</span>.</p>\n"

I hope this can help someone else trying to do some markdown-it-py customizations.