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

(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

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Deserialize this value from the given Serde deserializer. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
Serialize this value into the given Serde serializer. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Compare self to key and return true if they are equal.

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Converts self into a collection.
Should always be Self
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.
Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more