Struct Overridable

pub struct Overridable<T, const DEFAULT: isize = 500> { /* private fields */ }

An overridable value based on priority.

This is a wrapper that provides the “magic” mechanism by which values can be overridden across modules. After evaluating all modules, an Override<T> will keep the value with the least priority.

If the priority of a value is not given, the default of 500 is assumed. This can be changed by the DEFAULT type parameter. If you need to change this default, it is strongly recommended you make a type alias to avoid specifying the default priority on each use.

Example

let a = Overridable::with_priority("foo", 10);
let b = Overridable::with_priority("bar", 5);

let merged: Overridable<&str> = a.merge(b).unwrap();

assert_eq!(*merged, "bar");

serde

This type deserializes as one of the following:

• T
• { value: T }
• { value: T, priority: isize }

Implementations

impl<T, const DEFAULT: isize> Overridable<T, DEFAULT>

pub fn new(value: T) -> Self

Create a new value with the default priority.

pub fn with_priority<P>(value: T, priority: P) -> Self

where P: Into<Priority>,

Create a new value with priority.

pub fn priority(&self) -> Priority

Get the priority of this value.

pub fn set_priority<P>(&mut self, priority: P)

where P: Into<Priority>,

Set the priority of this value.

pub fn into_value(self) -> T

Destruct this Overridable and get the inner value.

Trait Implementations

impl<T, const DEFAULT: isize> AsMut<T> for Overridable<T, DEFAULT>

fn as_mut(&mut self) -> &mut T

Converts this type into a mutable reference of the (usually inferred) input type.

impl<T, const DEFAULT: isize> AsRef<T> for Overridable<T, DEFAULT>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<T, const DEFAULT: isize> Borrow<T> for Overridable<T, DEFAULT>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T, const DEFAULT: isize> BorrowMut<T> for Overridable<T, DEFAULT>

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value.

impl<T: Clone, const DEFAULT: isize> Clone for Overridable<T, DEFAULT>

fn clone(&self) -> Overridable<T, DEFAULT>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug, const DEFAULT: isize> Debug for Overridable<T, DEFAULT>

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

Formats the value using the given formatter.

impl<T, const DEFAULT: isize> Default for Overridable<T, DEFAULT>

where T: Default,

fn default() -> Self

Returns the “default value” for a type.

impl<T, const DEFAULT: isize> Deref for Overridable<T, DEFAULT>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T, const DEFAULT: isize> DerefMut for Overridable<T, DEFAULT>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'de, T, const DEFAULT: isize> Deserialize<'de> for Overridable<T, DEFAULT>

where T: Deserialize<'de>,

Available on crate feature serde only.

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T, const DEFAULT: isize> From<T> for Overridable<T, DEFAULT>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T, const DEFAULT: isize> Merge for Overridable<T, DEFAULT>

fn merge_ref(&mut self, other: Self) -> Result<(), Error>

Merge self with other without taking ownership of self.

fn merge(self, other: Self) -> Result<Self, Error>

Merge self with other.

impl<T: Copy, const DEFAULT: isize> Copy for Overridable<T, DEFAULT>