markdown

An incremental Markdown parser and streaming terminal renderer, in Rust.

Parse incrementally. Render immediately. Keep memory bounded.

A Rust port of codewandler/markdown-go — built for rendering streaming output (e.g. an LLM's tokens) to a terminal as it arrives, without waiting for the whole document.

Status: under active construction. The workspace, parser contract, and the CommonMark/GFM compliance harness are in place; the parser and terminal renderer are being ported milestone by milestone (see the roadmap).

Why

• Streaming — feed bytes in any chunking; the event stream is identical regardless of how input is split (split-equivalence). Blocks are emitted as soon as they close.
• Bounded memory — proportional to unresolved (open) state, not document size.
• Terminal-first — themed ANSI output with width-aware wrapping, syntax-highlighted code, and a live renderer that redraws as content streams in. HTML output exists primarily to measure compliance.
• Compliance-driven — developed against the CommonMark 0.31.2 (652) and GFM (728) spec corpora.

Workspace

Published on crates.io under the codewandler- prefix; the import names stay short (use markdown::…, use markdown_stream::…).

Crate	crates.io	What
markdown-stream	codewandler-markdown-stream	the incremental parser + event model (pure std)
markdown-html	codewandler-markdown-html	events → HTML (the compliance oracle)
markdown-terminal	codewandler-markdown-terminal	events → styled terminal output (ANSI) + the live renderer
markdown-ratatui	codewandler-markdown-ratatui	events → ratatui Text for TUIs
markdown	codewandler-markdown	the top-level facade (render_string, html_string, parse)
mdview	—	the CLI (workspace-only; the name is taken on crates.io)

cargo add codewandler-markdown   # imported in code as `markdown`

Status

The streaming parser, the live terminal renderer, and the mdview CLI are working end to end:

• Parser — streaming blocks (headings, fenced code, blockquotes, bullet/ordered lists, thematic breaks, GFM tables) + inlines (emphasis, strong, code spans, links, images, strikethrough, autolinks, escapes, hard/soft breaks); chunk-safe (split-equivalent). CommonMark 219/652, GFM 222/672 and climbing.
• Terminal renderer — themed ANSI, width-aware word wrapping, indented lists/blockquotes, GFM tables with per-column alignment + box-drawing borders, and dependency-free syntax highlighting for fenced code. TTY / NO_COLOR aware (plain when piped).
• mdview — mdview FILE or … | mdview: render Markdown to the terminal, streaming.

printf '# Hi\n\n- **bold** item\n\n```rust\nfn main() {}\n```\n' | cargo run -q -p mdview

Next

• Full CommonMark/GFM compliance (the corpora ratchet upward), nested lists, setext headings, reference links, indented code.
• HTML table rendering; the live in-place redraw of streaming tables; a ratatui viewport; criterion benchmarks vs pulldown-cmark/comrak/termimad.

License

MIT OR Apache-2.0