random¶

A seedable pseudo-random generator for ints and floats.

import "std/random" as random;

The generator is a PCG32 instance shared by the whole program. On the first call that draws a number it seeds itself from the clock, so a run without an explicit seed differs each time. Call seed to make a run repeatable.

The sequence is not suitable for cryptography.

The module binds a small dynamic library, so it is one of the three std modules that need that library present at run time. A .cdlb built from a program that imports std/random records the binding by name and re-opens it when the artifact runs; see artifacts.

seed¶

random::seed(s)

• s: an int.
• Returns: nothing.

Restarts the generator from s. Two runs seeded with the same value draw the same sequence.

random_int¶

random::random_int()

• Returns: an int drawn from the generator's full range, so the result can be negative.

random_int_range¶

random::random_int_range(min, max)

• min, max: ints.
• Returns: an int between min and max, with both ends included.

import "std/random" as random;

fn main() {
    random::seed(42);
    print(random::random_int_range(1, 6));
}

random¶

random::random()

• Returns: a float in the half-open range from 0 up to 1.

random_range¶

random::random_range(min, max)

• min, max: floats.
• Returns: a float between min and max, including min and excluding max.