Random

Random, part of the util module, is a random generator.

• Random{} creates a Random object, with optional paramerer seed:int
• various methods are available to generate different types of random values, from a uniform distribution: int, float, geo
• normal, uniform and gaussian can be used to draw values from.

fn gen_three(r: Random) {
    for (var i = 0; i < 3; i++) {
        println(r.uniform(0,100));
    }
}

fn main() {
    var random = Random{seed:10};
    gen_three(random);
    gen_three(random);
}

greycat run will display 6 different integers. However, re-runnning the program will generate the same sequence.

To save the state across program executions, you can do something like:

var nodeRandom: node<Random?>;

fn gen_three_stateful() {
    var random = nodeRandom.resolve();
    if (random == null) {
        info("setting R");
        random = Random{seed:10};
        nodeRandom = node<Random>{random};
    }
    for (var i = 0; i < 3; i++) {
        println(random.uniform(0,100));
    }
}

The info command signals the object creation.

Deleting the gcdata directory will remove the saved Random object, and generate the same initial sequence.