Module serial::markdown

Markdown.

Unlike json.h/xml.h/html.h, Markdown doesn't map onto the generic Value tree (std/serial/value.h) — it's document markup (headings, paragraphs, lists, emphasis), not key/value data — so this is its own AST, parsed from CommonMark (plus opt-in GitHub-flavored and documentation-site extensions) and rendered to HTML or back to Markdown.

Blocks: ATX and setext headings, paragraphs, thematic breaks, block quotes, bullet and ordered lists (nested, tight or loose, items holding any blocks), fenced code (``` / ~~~, with an info string) and indented code. Inlines: emphasis and strong emphasis with CommonMark's delimiter rules (no intraword '_'), code spans, backslash escapes, entity and numeric character references, links and images (inline form, with titles; link text holds any inlines), scheme:... and <email> autolinks, hard line breaks. Not supported: reference-style links ('[x][ref]' / '[ref]: url') and footnotes.

Opt-in through MdOptions (MdNode::parse_opts):

tables         GFM tables, with column alignment ('| a | b |' + '|:--|--:|')
html           raw HTML blocks and inline tags pass through unescaped
               (off by default: untrusted input stays inert)
containers     '::: kind [title]' ... ':::' blocks (tip, warning,
               details, ... — any word), nestable
heading_ids    '## Title {#custom-id}', and an id for every other
               heading from md_slugify (deduplicated with -1, -2, ...)
strikethrough  '~~text~~'
autolinks      bare 'https://...', 'http://...' and 'www....' URLs

MdOptions::commonmark() turns all of them off (what MdNode::parse uses); MdOptions::gfm() turns on tables, strikethrough and autolinks.

struct MdOptions o = MdOptions::gfm();
o.html = 1; o.containers = 1; o.heading_ids = 1;
&heap MdNode doc = MdNode::parse_opts(text, &o);
struct String html = doc.render_html();
doc.free();

md_render_html_with renders with a hook that can replace or wrap any node's HTML (rewrite link targets, add heading anchors, highlight code).