Crate serde_yaml

  

This crate is a Rust library for using the Serde serialization framework with data in YAML file format.

Examples

use std::collections::BTreeMap;

fn main() -> Result<(), serde_yaml::Error> {
    // You have some type.
    let mut map = BTreeMap::new();
    map.insert("x".to_string(), 1.0);
    map.insert("y".to_string(), 2.0);

    // Serialize it to a YAML string.
    let yaml = serde_yaml::to_string(&map)?;
    assert_eq!(yaml, "x: 1.0\ny: 2.0\n");

    // Deserialize it back to a Rust type.
    let deserialized_map: BTreeMap<String, f64> = serde_yaml::from_str(&yaml)?;
    assert_eq!(map, deserialized_map);
    Ok(())
}

Using Serde derive

It can also be used with Serde’s derive macros to handle structs and enums defined in your program.

Structs serialize in the obvious way:

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Point {
    x: f64,
    y: f64,
}

fn main() -> Result<(), serde_yaml::Error> {
    let point = Point { x: 1.0, y: 2.0 };

    let yaml = serde_yaml::to_string(&point)?;
    assert_eq!(yaml, "x: 1.0\ny: 2.0\n");

    let deserialized_point: Point = serde_yaml::from_str(&yaml)?;
    assert_eq!(point, deserialized_point);
    Ok(())
}

Enums serialize using YAML’s !tag syntax to identify the variant name.

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, PartialEq, Debug)]
enum Enum {
    Unit,
    Newtype(usize),
    Tuple(usize, usize, usize),
    Struct { x: f64, y: f64 },
}

fn main() -> Result<(), serde_yaml::Error> {
    let yaml = "
        - !Newtype 1
        - !Tuple [0, 0, 0]
        - !Struct {x: 1.0, y: 2.0}
    ";
    let values: Vec<Enum> = serde_yaml::from_str(yaml).unwrap();
    assert_eq!(values[0], Enum::Newtype(1));
    assert_eq!(values[1], Enum::Tuple(0, 0, 0));
    assert_eq!(values[2], Enum::Struct { x: 1.0, y: 2.0 });

    // The last two in YAML's block style instead:
    let yaml = "
        - !Tuple
          - 0
          - 0
          - 0
        - !Struct
          x: 1.0
          y: 2.0
    ";
    let values: Vec<Enum> = serde_yaml::from_str(yaml).unwrap();
    assert_eq!(values[0], Enum::Tuple(0, 0, 0));
    assert_eq!(values[1], Enum::Struct { x: 1.0, y: 2.0 });

    // Variants with no data can be written using !Tag or just the string name.
    let yaml = "
        - Unit  # serialization produces this one
        - !Unit
    ";
    let values: Vec<Enum> = serde_yaml::from_str(yaml).unwrap();
    assert_eq!(values[0], Enum::Unit);
    assert_eq!(values[1], Enum::Unit);

    Ok(())
}

Modules

• mapping
  A YAML mapping and its iterator types.
• value
  The Value enum, a loosely typed way of representing any valid YAML value.
• with
  Customizations to use with Serde’s #[serde(with = …)] attribute.

Structs

• Deserializer
  A structure that deserializes YAML into Rust values.
• Error
  An error that happened serializing or deserializing YAML data.
• Location
  The input location that an error occured.
• Mapping
  A YAML mapping in which the keys and values are both serde_yaml::Value.
• Number
  Represents a YAML number, whether integer or floating point.
• Serializer
  A structure for serializing Rust values into YAML.

Enums

• Value
  Represents any valid YAML value.

Traits

• Index
  A type that can be used to index into a serde_yaml::Value. See the get and get_mut methods of Value.

Functions

• from_reader
  Deserialize an instance of type T from an IO stream of YAML.
• from_slice
  Deserialize an instance of type T from bytes of YAML text.
• from_str
  Deserialize an instance of type T from a string of YAML text.
• from_value
  Interpret a serde_yaml::Value as an instance of type T.
• to_string
  Serialize the given data structure as a String of YAML.
• to_value
  Convert a T into serde_yaml::Value which is an enum that can represent any valid YAML data.
• to_writer
  Serialize the given data structure as YAML into the IO stream.

Type Definitions

• Result
  Alias for a Result with the error type serde_yaml::Error.
• Sequence
  A YAML sequence in which the elements are serde_yaml::Value.