bezel

Patterns / Media

Markdown

Markdown apps/gallery/src/patterns/dialect.rs 

let doc = markdown::parse(source);
let source = markdown::serialize(&doc);

The document model is Notion's — a flat list of blocks, each carrying an indent — and markdown is its wire form. parse and serialize are inverses up to a fixed point: parse, serialize, parse again, and nothing has moved.

Blocks

Spelling Block
# … ###### Heading, levels 1–6
plain text Paragraph
- , * , + Bullet
1. Ordered item, keeping the number it starts at
- [ ] , - [x] Task
> Quote
``` Fence
--- Rule
| a | b | Table
![alt](url) alone on a line Picture
a link alone on a line Bookmark

A newline inside a block is a line break, here and in Notion both.

Marks

**bold**, _italic_ or *italic*, ~~strikethrough~~, `code`, and [text](url). Nesting order survives a round trip — **_x_** and _**x**_ are different documents, which is why marks are spans over the text rather than flags on a run.

Typing ## makes a heading because pasting ## would have; inline marks close on the last delimiter. Emphasis will not open or close against a space, and an underscore inside a word is not emphasis, which is the only reason snake_case_names survive being typed.

Fences

```rs
fn main() {}
```

A tag names the grammar syntax highlights with. A tag nothing claims paints plain and never fails. markdown::set_block_renderer hands a tag and its source to a function of yours, so ```chart paints as a chart and still holds a caret, still round trips byte for byte, and still degrades to its own source where the renderer is not installed.

Links and pictures

<https://bezel.gallery>
[https://bezel.gallery](https://bezel.gallery "chip")
[https://bezel.gallery](https://bezel.gallery "embed")
![A caption is the alt text|480](https://example.com/cover.png)

A link with a line to itself is a card; chip and embed have no shorthand, so they say their name in the title slot. What a card shows past its URL is the app's, through markdown::set_link_preview — the crate fetches nothing. A picture's caption is its alt text, and a dragged width is written after it in whole pixels.

Limits
nesting Four spaces per level, list nesting only. > - a flattens to the bullet it reads as; a list inside a quote inside a list does not survive.
normalized on parse Edge whitespace, blank lines at block edges, headings and table cells flattened to one line, ordered runs renumbered.
escaping Only at the start of a line, where the character would mean something — escape # everywhere and #123 becomes \#123, which no reader matches.
HTML Arrives as the text it spells and is written back escaped.
not carried Footnotes and reference-style definitions. A setext heading is read and written back as #.

Tables are GFM's, alignment row included — :---, :---:, ---:. Every cell is one line and holds a caret.

The source is at apps/gallery/src/patterns/dialect.rs. Copy the file.

Markdown