fix: preserve underscores in LaTeX math blocks during DOCX conversion#1924
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phanghonghao wants to merge 1 commit into
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fix: preserve underscores in LaTeX math blocks during DOCX conversion#1924phanghonghao wants to merge 1 commit into
phanghonghao wants to merge 1 commit into
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When converting DOCX files with OMML math formulas, the pipeline
converts OMML → LaTeX ($v_{c}$) → HTML (via mammoth) → Markdown
(via markdownify). The markdownify layer incorrectly escapes
underscores inside math delimiters, producing $v\_{c}$ instead
of $v_{c}$.
Add a post-processing step in `_CustomMarkdownify.convert_soup()`
that restores the correct LaTeX by unescaping `\_` → `_` and
`\*` → `*` inside both inline ($...$) and display ($$...$$) math
regions. Plain-text underscores outside math blocks are preserved
as escaped (correct Markdown behavior).
Related: microsoft#289
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
When converting DOCX files containing OMML math formulas, the conversion pipeline produces incorrect Markdown output because
markdownifyescapes underscores and asterisks inside LaTeX math delimiters.Bug:
$v_{c}$→$v\_{c}$(broken LaTeX)Fix: Post-process markdownify output to restore correct LaTeX inside
$...$and$$...$$math regions.Root Cause
The DOCX conversion pipeline is:
pre_process.pyconverts OMML → LaTeX string wrapped in$...$mammothconverts the modified DOCX → HTMLmarkdownifyconverts HTML → MarkdownAt step 3, markdownify treats
_and*as emphasis markers and escapes them, even inside math delimiters. This is documented in_markdownify.pyline 67:#29: text nodes underscores are escaped.Changes
_markdownify.py: Added_fix_math_escaping()post-processor inconvert_soup()that unescapes\_→_and\*→*inside$...$and$$...$$math blocks only. Plain-text underscores outside math remain escaped (correct Markdown behavior).test_math_escaping.py: 24 test cases covering:_fix_math_escaping()with various LaTeX patterns_CustomMarkdownify.convert_soup()Test Plan
pytest tests/test_math_escaping.py -v)🤖 Generated with Claude Code