Markdown Conformance

Lanexio Parser’s Markdown parser passes 100% of CommonMark 0.31.2 tests and 100% of GFM tests.

Serializer roundtrip

The Markdown serializer (serializeMarkdown) was delivered in phases MD-S1 through MD-S4. All CommonMark and GFM features roundtrip correctly: parse → serialize → re-parse produces AST-identical trees.

Phase	Features	Tests
MD-S1	Leaf blocks (thematic breaks, code blocks, HTML)	1,841
MD-S2	Headings, paragraphs, inline formatting	1,864
MD-S3	Links, images, blockquotes, lists	1,880
MD-S4	GFM tables, character escaping, golden roundtrip	1,898

Test suite results

Suite	Tests	Passed	Failed
CommonMark 0.31.2	652	652	0
GitHub Flavored Markdown	648	648	0
Total	1,300	1,300	0

The full results and per-section breakdown are in docs/MARKDOWN_GAPS.md in the repository.

CommonMark spec coverage

All 652 CommonMark 0.31.2 spec examples pass. Covered sections include:

Section	Examples
Thematic breaks	19
ATX headings	16
Setext headings	26
Indented code blocks	12
Fenced code blocks	29
HTML blocks	44
Link reference definitions	27
Paragraphs	8
Block quotes	25
List items	48
Lists	26
Backslash escapes	13
Entity references	12
Code spans	17
Emphasis and strong emphasis	131
Links	68
Images	22
Autolinks	19
Raw HTML	21
Hard line breaks	15
Soft line breaks	2
Textual content	1

GFM spec coverage

All 648 GFM-specific examples pass. GFM extensions covered:

Extension	Status
Tables	Implemented
Task list items	Implemented
Strikethrough	Implemented
Autolinks (extended)	Implemented
Disallowed raw HTML	Implemented

GFM is default

GFM extensions are enabled by default in parseMarkdown. Pass { gfm: false } for strict CommonMark-only parsing.

Spec references

CommonMark 0.31.2 specification
RAG: commonmark_docs::spec@0.31.2

GitHub Flavored Markdown specification
RAG: gfm_docs::spec@gfm-0.29.0