markdown-frontmatter 0.5.1

# markdown-frontmatter

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A type-safe parser for Markdown frontmatter.

This crate provides a simple and efficient way to split and parse frontmatter
from Markdown documents.

## Supported Frontmatter Formats

The crate supports the following frontmatter formats and their corresponding
delimiters:

- **JSON**: Delimited by `{` on the first line and `}` on a closing line. The
  enclosed JSON content must be indented to be parsed correctly.
  ```text
  {
    "title": "JSON Frontmatter"
  }
  ```
- **TOML**: Delimited by `+++` on opening and closing lines.
  ```text
  +++
  title = "TOML Frontmatter"
  +++
  ```
- **YAML**: Delimited by `---` on opening and closing lines.
  ```text
  ---
  title: YAML Frontmatter
  ---
  ```

## Usage

Add the crate to your dependencies:

```sh
cargo add markdown-frontmatter
```

### Parsing Frontmatter

```rust
#[derive(serde::Deserialize)]
struct Frontmatter {
    title: String,
}

let doc = r#"---
title: Hello
---
World"#;

let (frontmatter, body) = markdown_frontmatter::parse::<Frontmatter>(doc).unwrap();
assert_eq!(frontmatter.title, "Hello");
assert_eq!(body, "World");
```

#### Optional frontmatter

If a document does not contain a frontmatter, it is treated as if it has an
empty one. This allows to make frontmatter fully optional by using only optional
fields, e.g.

```rust
#[derive(serde::Deserialize)]
struct Frontmatter {
    title: Option<String>,
}

let doc = "Hello";
let (frontmatter, body) = markdown_frontmatter::parse::<Frontmatter>(doc).unwrap();
assert!(frontmatter.title.is_none());
assert_eq!(body, "Hello");
```

## Features

This crate has the following Cargo features:

- `json`: Enables JSON frontmatter parsing.
- `toml`: Enables TOML frontmatter parsing.
- `yaml`: Enables YAML frontmatter parsing.

By default, no features are enabled.

## Contributing

Before submitting a pull request, please run the [.pre-commit.sh] script:

```sh
./.pre-commit.sh
```

## License

This project is licensed under the [MIT license][license].

[.pre-commit.sh]:
  https://github.com/imbolc/markdown-frontmatter/blob/main/.pre-commit.sh
[license]: https://github.com/imbolc/markdown-frontmatter/blob/main/LICENSE