Created
January 1, 2021 22:20
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use std::ops::{Add, Mul, Sub}; | |
macro_rules! assert_equal_len { | |
// The `tt` (token tree) designator is used for | |
// operators and tokens. | |
($a:expr, $b:expr, $func:ident, $op:tt) => { | |
assert!($a.len() == $b.len(), | |
"{:?}: dimension mismatch: {:?} {:?} {:?}", | |
stringify!($func), | |
($a.len(),), | |
stringify!($op), | |
($b.len(),)); | |
}; | |
} | |
macro_rules! op { | |
($func:ident, $bound:ident, $op:tt, $method:ident) => { | |
fn $func<T: $bound<T, Output=T> + Copy>(xs: &mut Vec<T>, ys: &Vec<T>) { | |
assert_equal_len!(xs, ys, $func, $op); | |
for (x, y) in xs.iter_mut().zip(ys.iter()) { | |
*x = $bound::$method(*x, *y); | |
// *x = x.$method(*y); | |
} | |
} | |
}; | |
} | |
// Implement `add_assign`, `mul_assign`, and `sub_assign` functions. | |
op!(add_assign, Add, +=, add); | |
op!(mul_assign, Mul, *=, mul); | |
op!(sub_assign, Sub, -=, sub); | |
mod test { | |
use std::iter; | |
macro_rules! test { | |
($func:ident, $x:expr, $y:expr, $z:expr) => { | |
#[test] | |
fn $func() { | |
for size in 0usize..10 { | |
let mut x: Vec<_> = iter::repeat($x).take(size).collect(); | |
let y: Vec<_> = iter::repeat($y).take(size).collect(); | |
let z: Vec<_> = iter::repeat($z).take(size).collect(); | |
super::$func(&mut x, &y); | |
assert_eq!(x, z); | |
} | |
} | |
}; | |
} | |
// Test `add_assign`, `mul_assign`, and `sub_assign`. | |
test!(add_assign, 1u32, 2u32, 3u32); | |
test!(mul_assign, 2u32, 3u32, 6u32); | |
test!(sub_assign, 3u32, 2u32, 1u32); | |
} |
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