:sig
DValue markdown_to_ast(String src)
DValue markdown_to_ast(String src, DValue options)

:params
src : markdown source text
options : optional markdown options tree
return value : a `DValue` document AST

:see
markdown_to_html
component
component_render
json_encode
0_DValue

:content
Parses Markdown source into a structured `DValue` document tree.

The parser targets a practical GitHub-flavored subset by default:

- ATX headings with `#`
- setext headings
- paragraphs
- blockquotes
- ordered and unordered lists
- task list items
- fenced code blocks
- tables
- horizontal rules
- emphasis, strong, and strikethrough
- links, images, autolinks, and code spans
- `:::` directive blocks for component-based extensions

The returned AST uses `type` plus node-specific fields such as `level`, `text`, `lang`, `href`, `src`, `name`, `argument`, `attrs`, and `children`.

Top-level documents use:

```text
type = "document"
children = [...]
```

Common block nodes:

- `heading`
- `paragraph`
- `blockquote`
- `list`
- `list_item`
- `code_block`
- `table`
- `directive`
- `hr`

Common inline nodes:

- `text`
- `code`
- `strong`
- `em`
- `strike`
- `link`
- `image`
- `raw_html`

Example:

```uce
DValue options = json_decode("{\"components\":{\":::warning\":\"components/markdown/warning\"}}");
DValue ast = markdown_to_ast(file_get_contents("README.md"), options);
print(json_encode(ast));
```

Options:

- `options["gfm"]` enables GitHub-style extras such as tables, task lists, strikethrough, and bare-URL autolinks. Defaults to `true`.
- `options["allow_html"]` allows raw HTML passthrough nodes to be captured and rendered. Defaults to `false`.
- `options["components"]` provides the component hook map later used by `markdown_to_html()`. The parser preserves directive data needed by those hooks.

Related:

- PHP: CommonMark or Parsedown parsing pipelines that expose a syntax tree or token stream
- JavaScript / Node.js: `remark`, `micromark`, or `markdown-it` token streams and AST-like structures