10 releases
0.2.8 | May 27, 2024 |
---|---|
0.2.6 | Apr 8, 2023 |
0.2.5 | Jan 13, 2023 |
0.2.4 | Jul 22, 2022 |
0.1.0 | Feb 7, 2021 |
#97 in Parser implementations
10,354 downloads per month
Used in 18 crates
(16 directly)
56KB
1.5K
SLoC
gray_matter is a tool for easily extracting front matter out of a string. It is a fast Rust implementation of gray-matter. It supports the following front matter formats:
- TOML
- YAML
- JSON
It also has an Engine
trait interface for implementing your own parsers that work with gray_matter.
Usage
Add gray_matter
as a dependency
Append this crate to the Cargo.toml
:
[dependencies]
# other dependencies...
gray_matter = "0.2"
Basic parsing
use gray_matter::Matter;
use gray_matter::engine::YAML;
use serde::Deserialize;
const INPUT: &str = r#"---
title: gray-matter-rs
tags:
- gray-matter
- rust
---
Some excerpt
---
Other stuff
"#;
fn main() {
// Select one parser engine, such as YAML, and parse it
// into gray_matter's custom data type: `Pod`
let matter = Matter::<YAML>::new();
let result = matter.parse(INPUT);
// You can now inspect the data from gray_matter.
assert_eq!(result.content, "Some excerpt\n---\nOther stuff");
assert_eq!(result.excerpt, Some("Some excerpt".to_owned()));
assert_eq!(result.data.as_ref().unwrap()["title"].as_string(), Ok("gray-matter-rs".to_string()));
assert_eq!(result.data.as_ref().unwrap()["tags"][0].as_string(), Ok("gray-matter".to_string()));
assert_eq!(result.data.as_ref().unwrap()["tags"][1].as_string(), Ok("rust".to_string()));
// The `Pod` data type can be a bit unwieldy, so
// you can also deserialize it into a custom struct
#[derive(Deserialize, Debug)]
struct FrontMatter {
title: String,
tags: Vec<String>
}
// Deserialize `result` manually:
let front_matter: FrontMatter = result.data.unwrap().deserialize().unwrap();
println!("{:?}", front_matter);
// FrontMatter { title: "gray-matter-rs", tags: ["gray-matter", "rust"] }
// ...or skip a step, by using `parse_with_struct`.
let result_with_struct = matter.parse_with_struct::<FrontMatter>(INPUT).unwrap();
println!("{:?}", result_with_struct.data)
// FrontMatter { title: "gray-matter-rs", tags: ["gray-matter", "rust"] }
}
Custom Delimiters
The default delimiter is ---
, both for front matter and excerpts. You can change this by modifiying the Matter
struct.
use gray_matter::{Matter, ParsedEntityStruct};
use gray_matter::engine::YAML;
use serde::Deserialize;
fn main() {
let mut matter: Matter<YAML> = Matter::new();
matter.delimiter = "~~~".to_owned();
matter.excerpt_delimiter = Some("<!-- endexcerpt -->".to_owned());
#[derive(Deserialize, Debug)]
struct FrontMatter {
abc: String,
}
let result: ParsedEntityStruct<FrontMatter> = matter.parse_with_struct(
"~~~\nabc: xyz\n~~~\nfoo\nbar\nbaz\n<!-- endexcerpt -->\ncontent",
).unwrap();
}
Custom close delimiter
The open and close delimiter are the same by default (---
). You can change this by modifiying close_delimiter
property of Matter
struct
use gray_matter::{Matter, ParsedEntityStruct};
use gray_matter::engine::YAML;
use serde::Deserialize;
fn main() {
let mut matter: Matter<YAML> = Matter::new();
matter.delimiter = "<!--".to_owned();
matter.close_delimiter = Some("-->".to_owned());
matter.excerpt_delimiter = Some("<!-- endexcerpt -->".to_owned());
#[derive(Deserialize, Debug)]
struct FrontMatter {
abc: String,
}
let result: ParsedEntityStruct<FrontMatter> = matter.parse_with_struct(
"<!--\nabc: xyz\n-->\nfoo\nbar\nbaz\n<!-- endexcerpt -->\ncontent",
).unwrap();
}
Contributors
Contribution
If you need more parser engines, feel free to create a PR to help me complete this crate.
Dependencies
~2.8–4MB
~70K SLoC