Matthias Benkard | 848739c | 2019-02-28 13:59:58 +0100 | [diff] [blame^] | 1 | // Generic Programming: Static Polymorphism |
Matthias Benkard | f3a3b30 | 2019-02-28 12:13:56 +0100 | [diff] [blame] | 2 | |
| 3 | #![allow(dead_code)] |
| 4 | #![allow(unused_imports)] |
| 5 | |
| 6 | use rust_tutorial::*; |
| 7 | |
| 8 | /// Run this to see the disassembly of `compute_sum_of_squares_{1,2}`: |
| 9 | /// |
| 10 | /// ```bash |
Matthias Benkard | 848739c | 2019-02-28 13:59:58 +0100 | [diff] [blame^] | 11 | /// cargo objdump --bin tut3 --release -- -d | awk -v RS= '/^([[:xdigit:]]+ )?tut3::compute_sum_of_squares/' |
Matthias Benkard | f3a3b30 | 2019-02-28 12:13:56 +0100 | [diff] [blame] | 12 | /// ``` |
| 13 | |
| 14 | #[inline(never)] |
| 15 | fn compute_sum_of_squares_i32(zero: i32, xs: &Vec<i32>) -> i32 { |
| 16 | xs[1..].iter() |
| 17 | .map(|x| x * x) |
| 18 | .fold(zero, |acc, x| acc + x) |
| 19 | } |
| 20 | |
| 21 | #[inline(never)] |
| 22 | fn compute_sum_of_squares<T>(zero: T, xs: &Vec<T>) -> T |
| 23 | where |
| 24 | T: std::ops::Mul<Output=T> + std::ops::Add<Output=T> + Copy |
| 25 | { |
| 26 | xs[1..].iter() |
| 27 | .map(|x| *x * *x) |
| 28 | .fold(zero, |acc, x| acc + x) |
| 29 | } |
| 30 | |
| 31 | fn main() { |
| 32 | let numbers = vec![1, 2, 3, 4, 5]; |
| 33 | |
| 34 | let sum_of_squares_i32 = compute_sum_of_squares_i32(0, &numbers); |
| 35 | let sum_of_squares_t = compute_sum_of_squares(0, &numbers); |
| 36 | |
| 37 | println!("sum i32 = {}", sum_of_squares_i32); |
| 38 | println!("sum T = {}", sum_of_squares_t); |
| 39 | } |