Fix: LaTeX equations being misrendered

[jeongHwarr]

Problem

When uploading Markdown files containing LaTeX math expressions to Notion via NotionPyRenderer, expressions like the one below are incorrectly rendered:

  - expressions: $$\hat{\boldsymbol{x}}_{\sigma_{t}}=\hat{\boldsymbol{x}}_{\sigma_{t}} \odot(1-\mathbf{m})+\boldsymbol{x}_{\sigma_{t}} \odot \mathbf{m}$$

In particular, underscores (_) are misinterpreted as emphasis markers (*) due to the following renderer method:

def render_emphasis(self, token):
    return self.renderMultipleToStringAndCombine(token.children, lambda s: f"*{s}*")

Notion result:

\hat{\boldsymbol{x}}*{\sigma*{t}}=\hat{\boldsymbol{x}}*{\sigma*{t}} \odot(1-\mathbf{m})+\boldsymbol{x}*{\sigma*{t}} \odot \mathbf{m}

This causes math symbols to be transformed unintentionally.

Solution

To address this, LaTeX equations (both block and inline using $$) are:

• Extracted and temporarily replaced with unique placeholders before rendering.
• Rendered using NotionPyRenderer.
• Restored into the final Notion-compatible structure using the original math expressions.

This ensures math expressions are rendered correctly and safely in Notion without being altered by the Markdown emphasis rules.

Changes

• Added extract_equations() to parse and replace math blocks with placeholders
• Added restore_equations_in_rendered() to restore math expressions after rendering
• Updated read_file() flow to apply extraction → rendering → restoration
• Modified Document class to better tokenize math blocks using $$ line markers

[jeongHwarr]

Related issue: https://github.com/veya2ztn/md2notion_api_version/issues/5