- Drop the outer no-op capture group from INLINE_RE and restructure the
source as an ordered list of patterns-with-index-comments so each
alternative is individually greppable. Shift group indices in MdInline
down by one accordingly.
- Inline single-use helpers (parseFence, isFenceClose, isMarkdownFence,
trimBareUrl) and intermediate variables (path, lang, raw, prefix, body,
depth, task body, setext match, etc.).
- Hoist block-level regexes used inside MdImpl (FENCE_CLOSE_RE, SETEXT_RE,
BULLET_RE, TASK_RE, NUMBERED_RE, QUOTE_RE) to top-level consts so
they're compiled once instead of per-line.
- Collapse the duplicate compact-vs-normal blank-line branches into one
if/!compact gap call.
- Move Fence and MdProps types to the bottom per house style.
- Shorten splitTableRow → splitRow and use optional chaining in a few
match sites.
No behavior change; 162/162 tests pass. Net -22 LoC.