Code block fencing: 2.7x fewer fenced blocks than docling across 38 papers

[sentientsergio]

We ran a full evaluation of tomd against docling on the 38 PDF papers in the 2026-02 pre-Croydon mailing. Full report with side-by-side markdowns: https://github.com/cppalliance/paperlint-eval/blob/main/tomd-eval/report.md

tomd retains 476 code block fences across the corpus vs docling's 1,270 (2.7x gap). This is the primary blocker for adoption in the paperlint evaluation pipeline, where evidence quotes must be findable as substrings in the extracted text.

Specific papers where code is affected:

• P3984R0 — code examples rendered as bold inline text instead of fenced blocks. Compare docling.
• P3181R1 — multi-thread code examples fragmented into inline code spans. Compare docling.
• P3596R0 — 226 fences in docling, 4 in tomd.
• P4003R0 — 196 fences in docling, 4 in tomd. Code identifiers wrapped in :::wording blocks.
• P3844R4 — 54 fences in docling, 0 in tomd.

Fixing this would substantially close the gap for pipeline adoption.

[sentientsergio]

Concrete examples for developers:

P3984R0 Section 2.6 (Stroustrup profiles paper)

docling (correct -- fenced block):

void f(vector<int>& v) { v.push_back(7); } void g() { vector v = {1,2}; ...

tomd (broken -- bold inline text):

**void f(vector<int>& v)** **{** **v.push_back(7);** **}** **void g()** **{**

The code is rendered as a sequence of bold spans instead of a fenced code block.

P3181R1 (Boehm atomic stores paper)

docling produces 4 fenced code blocks showing Thread A / Thread B / Thread C concurrency scenarios. tomd does not produce any fenced blocks -- the multi-thread pseudocode (starting "Thread A: fence(release);") is not present as a code block in tomd's output.

P3596R0

docling: 226 fenced code blocks. tomd: 4. The paper is heavily code-based and almost all of it is lost in tomd's output.

The fix should ensure that when the PDF contains monospace/preformatted text regions, tomd emits them as fenced markdown code blocks.

[sentientsergio]

Source PDFs for reproduction:

• P3984R0: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p3984r0.pdf
• P3181R1: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p3181r1.pdf
• P3596R0: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p3596r0.pdf
• P4003R0: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p4003r0.pdf
• P3844R4: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2026/p3844r4.pdf

Run tomd <file>.pdf and check whether the output has fenced code blocks for the code samples visible in the PDF.