Trait nom::lib::std::ops::Mul 1.0.0
[−]
[src]
#[lang = "mul"]pub trait Mul<RHS = Self> { type Output; fn mul(self, rhs: RHS) -> Self::Output; }
The multiplication operator *
.
Note that RHS
is Self
by default, but this is not mandatory.
Examples
Mul
tipliable rational numbers
use std::ops::Mul; // By the fundamental theorem of arithmetic, rational numbers in lowest // terms are unique. So, by keeping `Rational`s in reduced form, we can // derive `Eq` and `PartialEq`. #[derive(Debug, Eq, PartialEq)] struct Rational { nominator: usize, denominator: usize, } impl Rational { fn new(nominator: usize, denominator: usize) -> Self { if denominator == 0 { panic!("Zero is an invalid denominator!"); } // Reduce to lowest terms by dividing by the greatest common // divisor. let gcd = gcd(nominator, denominator); Rational { nominator: nominator / gcd, denominator: denominator / gcd, } } } impl Mul for Rational { // The multiplication of rational numbers is a closed operation. type Output = Self; fn mul(self, rhs: Self) -> Self { let nominator = self.nominator * rhs.nominator; let denominator = self.denominator * rhs.denominator; Rational::new(nominator, denominator) } } // Euclid's two-thousand-year-old algorithm for finding the greatest common // divisor. fn gcd(x: usize, y: usize) -> usize { let mut x = x; let mut y = y; while y != 0 { let t = y; y = x % y; x = t; } x } assert_eq!(Rational::new(1, 2), Rational::new(2, 4)); assert_eq!(Rational::new(2, 3) * Rational::new(3, 4), Rational::new(1, 2));
Multiplying vectors by scalars as in linear algebra
use std::ops::Mul; struct Scalar { value: usize } #[derive(Debug, PartialEq)] struct Vector { value: Vec<usize> } impl Mul<Scalar> for Vector { type Output = Vector; fn mul(self, rhs: Scalar) -> Vector { Vector { value: self.value.iter().map(|v| v * rhs.value).collect() } } } let vector = Vector { value: vec![2, 4, 6] }; let scalar = Scalar { value: 3 }; assert_eq!(vector * scalar, Vector { value: vec![6, 12, 18] });
Associated Types
type Output
The resulting type after applying the *
operator.