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Trait elliptic_curve::ops::Sub

1.0.0 · source · [−]
pub trait Sub<Rhs = Self> {
    type Output;
    fn sub(self, rhs: Rhs) -> Self::Output;
}
Expand description

The subtraction operator -.

Note that Rhs is Self by default, but this is not mandatory. For example, std::time::SystemTime implements Sub<Duration>, which permits operations of the form SystemTime = SystemTime - Duration.

Examples

Subtractable points

use std::ops::Sub;

#[derive(Debug, Copy, Clone, PartialEq)]
struct Point {
    x: i32,
    y: i32,
}

impl Sub for Point {
    type Output = Self;

    fn sub(self, other: Self) -> Self::Output {
        Self {
            x: self.x - other.x,
            y: self.y - other.y,
        }
    }
}

assert_eq!(Point { x: 3, y: 3 } - Point { x: 2, y: 3 },
           Point { x: 1, y: 0 });

Implementing Sub with generics

Here is an example of the same Point struct implementing the Sub trait using generics.

use std::ops::Sub;

#[derive(Debug, PartialEq)]
struct Point<T> {
    x: T,
    y: T,
}

// Notice that the implementation uses the associated type `Output`.
impl<T: Sub<Output = T>> Sub for Point<T> {
    type Output = Self;

    fn sub(self, other: Self) -> Self::Output {
        Point {
            x: self.x - other.x,
            y: self.y - other.y,
        }
    }
}

assert_eq!(Point { x: 2, y: 3 } - Point { x: 1, y: 0 },
           Point { x: 1, y: 3 });

Associated Types

The resulting type after applying the - operator.

Required methods

Performs the - operation.

Example
assert_eq!(12 - 1, 11);

Implementations on Foreign Types

Returns the difference of self and rhs as a new BTreeSet<T>.

Examples
use std::collections::BTreeSet;

let a = BTreeSet::from([1, 2, 3]);
let b = BTreeSet::from([3, 4, 5]);

let result = &a - &b;
let result_vec: Vec<_> = result.into_iter().collect();
assert_eq!(result_vec, [1, 2]);

Returns the difference of self and rhs as a new HashSet<T, S>.

Examples
use std::collections::HashSet;

let a = HashSet::from([1, 2, 3]);
let b = HashSet::from([3, 4, 5]);

let set = &a - &b;

let mut i = 0;
let expected = [1, 2];
for x in &set {
    assert!(expected.contains(x));
    i += 1;
}
assert_eq!(i, expected.len());

UTerm - UTerm = UTerm

UInt<UTerm, B1> - B1 = UTerm

N(Ul) - N(Ur): We resolve this with our PrivateAdd

UInt - B0 = UInt

N(Ul) - P(Ur) = N(Ul + Ur)

UInt<U, B1> - B1 = UInt<U, B0>

P(Ul) - P(Ur): We resolve this with our PrivateAdd

Subtracting unsigned integers. We just do our PrivateSub and then Trim the output.

UTerm - B0 = Term

PInt - Z0 = PInt

P(Ul) - N(Ur) = P(Ul + Ur)

NInt - Z0 = NInt

UInt<U, B0> - B1 = UInt<U - B1, B1>

Implementors

Z0 - Z0 = Z0

Z0 - N = P

Z0 - P = N