markast 1.0.2

Markdown → typed AST → JSON / Markdown / HTML, with a pluggable widget system.

markast

Markdown → typed AST → JSON / Markdown / HTML

Parse Markdown into a structured, typed tree your front-end can render — natively, server-side, or as JSON.

Docs · Documentación (ES) · Examples

---

from markast import parse

doc = parse("# Hello\n\nA paragraph with **bold** and a [link](https://example.com).")

doc.to_json()       # str — ship to any client renderer
doc.to_markdown()   # str — roundtrip
doc.to_html()       # str — server-side render

Why a tree, not HTML?

HTML is a one-way street. Once your content is rendered, the structure is gone — clients can't restyle headings per platform, can't swap a :::video for a native player, can't extract a TOC without re-parsing.

markast keeps the meaning intact. Parse once, render anywhere:

• Native mobile renders headings with platform typography.
• The web renders :::video as a custom player; the terminal renders it as a link.
• Search indexes the same structured nodes that drive the UI.
• One source of content powers a docs site, a CMS preview, and a CLI.

What you get

Layer	What it gives you
🌳 AST	Typed nodes (TypedDict), walker/visitor, JSON-Schema export, factory helpers
🧱 Widgets	:::widget containers with typed params, named slots, validation — and a per-parser registry, no global state
🛡️ Rules	Validation diagnostics that never crash — bad content is repaired and a warning is emitted
⚙️ Transforms	AST → AST passes: normalize, slugify, TOC, autolink
🔀 Renderers	Markdown (full roundtrip) and HTML (server-side) — both subclassable
🧰 Parser	CommonMark + GFM (tables, strikethrough, tasklists, autolinks) + footnotes + custom containers
⌨️ CLI	markast parse file.md --format json

Install

pip install markast

30-second tour

from markast import Parser
from markast.widgets import BaseWidget, WidgetParam

class CalloutWidget(BaseWidget):
    name = "callout"
    params = {
        "level": WidgetParam(str, default="info", choices=["info", "warn", "error"]),
        "title": WidgetParam(str, default=None),
    }

parser = Parser(widgets=[CalloutWidget], transforms=["normalize", "slugify"])

doc = parser.parse("""
# Welcome

:::callout level=warn title="Heads up"
This is **important** content.
:::
""")

print(doc.to_json(indent=2))
print(doc.to_html())

parser.parse(...) always returns a valid Document. Invalid input is repaired and reported on doc.warnings — the parser never raises on user content.

Documentation

Full docs live at cursland.github.io/markast (English / Español, light & dark).

🚀 Getting started	Install, parse, render
🌳 AST reference	Every node type and field
🧱 Widgets	Built-ins and authoring your own
⚙️ Transforms	Built-in passes and custom transforms
🔀 Renderers	Markdown, HTML, and subclassing
🧭 Walker & utilities	Traverse and mutate the AST safely
🌐 Client integration	Patterns for any front-end
🧩 Extending	Custom rules, plugins, tokenizers

Examples

Runnable scripts in examples/:

• basic_parse.py — simplest usage
• custom_widget.py — register a widget
• transform_pipeline.py — chain transforms
• render_html.py — server-side HTML
• api_backend.py — FastAPI handler returning AST JSON

Status

1.0.0 — first stable release. Backwards-compatible changes follow semver.

License

MIT © cursland