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LastSubject

Struct LastSubject 

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pub struct LastSubject(pub Subject);
Expand description

Newtype wrapper for “last wins” combination strategy.

When combining two LastSubject instances, the second subject is returned and the first is discarded. This is useful for scenarios where you want the most recent subject to take precedence.

§Semigroup Laws

This satisfies associativity trivially: last(last(a, b), c) = last(a, last(b, c)) = c

§Examples

use pattern_core::{Subject, Symbol, Combinable, LastSubject};
use std::collections::HashSet;

let s1 = LastSubject(Subject {
    identity: Symbol("alice".to_string()),
    labels: HashSet::new(),
    properties: Default::default(),
});

let s2 = LastSubject(Subject {
    identity: Symbol("bob".to_string()),
    labels: HashSet::new(),
    properties: Default::default(),
});

// Last wins - s1 is the last argument, so it wins
let result = s2.combine(s1);
assert_eq!(result.0.identity.0, "alice");

Tuple Fields§

§0: Subject

Trait Implementations§

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impl Clone for LastSubject

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fn clone(&self) -> LastSubject

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Combinable for LastSubject

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

Combines two values associatively. Read more
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impl PartialEq for LastSubject

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fn eq(&self, other: &LastSubject) -> bool

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

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

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Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.