Macro branch

macro_rules! branch {
    ( $( $branch:expr ),* $(,)? ) => { ... };
}

Available on crate feature std only.

Branches into one of the given expressions.

This macro dose essentially the same as branch_using instead of giving it some RNG, this macro will simply use the rand::rng(). However, this then requires std, unlike branch_using.

This macro turns something like this:

branch!(
    println!("First line."),
    println!("Second line?"),
    println!("Third line!"),
);

into something similar to this using the rand::rng():

match rand::rng().random_range(0..3) {
    0 => println!("First line."),
    1 => println!("Second line?"),
    2 => println!("Third line!"),
    _ => unreachable!(),
}

Examples

You can use functions, macros and other arbitrary expressions:

use random_branch::branch;

fn do_something() {
     println!("There is no such thing")
}
let thing = "fuliluf";

branch!(
    println!("A {} is an animal!", thing),
    {
        let thing = "lufiful";
        println!("Two {}s will never meet.", thing)
    },
    println!("Only a {} can see other {0}s.", thing),
    do_something(),
);

You can also use it as an expression to yield some randomly chosen value:

use random_branch::branch;

let num = branch!(
    10,
    10 + 11,
    2 * (10 + 11),
    85,
);
println!("The best number is {}", num);