A Roc library for random number generation

Forked from JanCVanB/roc-random, updated to build package and documentation, and do some maintenance -- we will move it back to JanCVanB soon I'm just helping with all the breaking changes.

This packages has basic functionality, but there's much more it could do. Any contributions & feedback are very welcome!

# Print a list of 10 random numbers in the range 25-75 inclusive.
main! = |_args|
    random_numbers
    |> List.map(Num.to_str)
    |> Str.join_with("\n")
    |> Stdout.line!

numbers_generator : Random.Generator (List U32)
numbers_generator =
    Random.list(Random.bounded_u32(25, 75), 10)

random_numbers : List U32
random_numbers =
    # we can ignore the updated seed value and just return the generated numbers
    { value: numbers } = Random.step(Random.seed(1234), numbers_generator)

    numbers

expect
    actual = random_numbers
    actual == [52, 34, 26, 69, 34, 35, 51, 74, 70, 39]

See the examples/*.roc files for more examples.

See the library documentation site for more info about its API.

• An external API that is similar to that of Elm's Random library
• An internal implementation that is similar to that of Rust's Rand library
• Compatible with every Roc platform (though some platforms may provide poor/constant seeding)
• Provides a variety of ergonomic abstractions

In order to receive a different sequence of outputs from this library between executions of your application, your Roc platform of choice must provide a random/pseudorandom/varying seed.

Otherwise, your pure functions will be responsible for providing Random's pure functions with a constant seed that will merely choose which predictable sequence you'll receive.