Enum Either

pub enum Either<A, B> {
    Left(A),
    Right(B),
}

(De)serializes as either a magic value A or any other deserializable value B.

An Either<A, B> deserializes as either an A or B, whichever succeeds first.

The usual Either implementation or an “untagged” enum does not allow its internal values to provide hints to the deserializer. These hints are required for magic values to work. By contrast, this Either does provide the appropriate hints.

Example

use serde::{Serialize, Deserialize};
use figment::{Figment, value::magic::{Either, RelativePathBuf, Tagged}};

#[derive(Debug, PartialEq, Deserialize, Serialize)]
struct Config {
    int_or_str: Either<Tagged<usize>, String>,
    path_or_bytes: Either<RelativePathBuf, Vec<u8>>,
}

fn figment<A: Serialize, B: Serialize>(a: A, b: B) -> Figment {
    Figment::from(("int_or_str", a)).merge(("path_or_bytes", b))
}

let config: Config = figment(10, "/a/b").extract().unwrap();
assert_eq!(config.int_or_str, Either::Left(10.into()));
assert_eq!(config.path_or_bytes, Either::Left("/a/b".into()));

let config: Config = figment("hi", "c/d").extract().unwrap();
assert_eq!(config.int_or_str, Either::Right("hi".into()));
assert_eq!(config.path_or_bytes, Either::Left("c/d".into()));

let config: Config = figment(123, &[1, 2, 3]).extract().unwrap();
assert_eq!(config.int_or_str, Either::Left(123.into()));
assert_eq!(config.path_or_bytes, Either::Right(vec![1, 2, 3].into()));

let config: Config = figment("boo!", &[4, 5, 6]).extract().unwrap();
assert_eq!(config.int_or_str, Either::Right("boo!".into()));
assert_eq!(config.path_or_bytes, Either::Right(vec![4, 5, 6].into()));

let config: Config = Figment::from(figment::providers::Serialized::defaults(Config {
    int_or_str: Either::Left(10.into()),
    path_or_bytes: Either::Left("a/b/c".into()),
})).extract().unwrap();

assert_eq!(config.int_or_str, Either::Left(10.into()));
assert_eq!(config.path_or_bytes, Either::Left("a/b/c".into()));

let config: Config = Figment::from(figment::providers::Serialized::defaults(Config {
    int_or_str: Either::Right("hi".into()),
    path_or_bytes: Either::Right(vec![3, 7, 13]),
})).extract().unwrap();

assert_eq!(config.int_or_str, Either::Right("hi".into()));
assert_eq!(config.path_or_bytes, Either::Right(vec![3, 7, 13]));

Variants

Left(A)

The “left” variant.

Right(B)

The “right” variant.

Trait Implementations

impl<A, B> Clone for Either<A, B>

where A: Clone, B: Clone,

fn clone(&self) -> Either<A, B>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<A, B> Debug for Either<A, B>

where A: Debug, B: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de, 'b, A, B> Deserialize<'de> for Either<A, B>

where 'de: 'b, A: Magic, B: Deserialize<'b>,

fn deserialize<D>( de: D, ) -> Result<Either<A, B>, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<A, B> Hash for Either<A, B>

where A: Hash, B: Hash,

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<A, B> Ord for Either<A, B>

where A: Ord, B: Ord,

fn cmp(&self, other: &Either<A, B>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<A, B> PartialEq for Either<A, B>

where A: PartialEq, B: PartialEq,

fn eq(&self, other: &Either<A, B>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<A, B> PartialOrd for Either<A, B>

where A: PartialOrd, B: PartialOrd,

fn partial_cmp(&self, other: &Either<A, B>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<A, B> Serialize for Either<A, B>

where A: Serialize, B: Serialize,

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<A, B> Eq for Either<A, B>

where A: Eq, B: Eq,

impl<A, B> StructuralPartialEq for Either<A, B>