commit | 153da344c5cbf5786fef3f791f7ebfd1a30e35be | [log] [tgz] |
---|---|---|
author | Nikolai Vazquez <nvazquez1297@gmail.com> | Mon Aug 14 19:24:38 2017 -0400 |
committer | Nikolai Vazquez <nvazquez1297@gmail.com> | Mon Aug 14 19:24:38 2017 -0400 |
tree | 3efaa4e95c733b02c1a948c3346d84611f971e16 | |
parent | 60ba9e5780f666a43c8f2e711aea363e5d09acfe [diff] |
Change derive behavior for enums with < 3 variants Enums with a single variant will simply have the inner type (if any) generated. This avoids extra calls on the Rng. Enums with two variants will generate a bool rather than a number in a range. This should be a much faster approach, although I have not tested it. These changes avoid calls to the unreachable!() macro, which generates a panic in unnecessary cases like these. This in turn may make the generated functions faster since unused instructions won't be loaded. Enums with 3 or more variants behave the same as before.
A Rust library for random number generators and other randomness functionality.
Add this to your Cargo.toml
:
[dependencies] rand = "0.3"
and this to your crate root:
extern crate rand;
There is built-in support for a random number generator (RNG) associated with each thread stored in thread-local storage. This RNG can be accessed via thread_rng, or used implicitly via random. This RNG is normally randomly seeded from an operating-system source of randomness, e.g. /dev/urandom on Unix systems, and will automatically reseed itself from this source after generating 32 KiB of random data.
let tuple = rand::random::<(f64, char)>(); println!("{:?}", tuple)
use rand::Rng; let mut rng = rand::thread_rng(); if rng.gen() { // random bool println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>()) }
It is also possible to use other RNG types, which have a similar interface. The following uses the “ChaCha” algorithm instead of the default.
use rand::{Rng, ChaChaRng}; let mut rng = rand::ChaChaRng::new_unseeded(); println!("i32: {}, u32: {}", rng.gen::<i32>(), rng.gen::<u32>())
derive(Rand)
You can derive the Rand
trait for your custom type via the #[derive(Rand)]
directive. To use this first add this to your Cargo.toml:
rand = "0.3" rand_derive = "0.3"
Next in your crate:
extern crate rand; #[macro_use] extern crate rand_derive; #[derive(Rand, Debug)] struct MyStruct { a: i32, b: u32, } fn main() { println!("{:?}", rand::random::<MyStruct>()); }
rand
is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, and LICENSE-MIT for details.