Exploring the Hare Programming Language

I'm currently running Alpine Linux on my Thinkpad, so the installation was quite easy as there is a package for Hare in the apk repositories.

doas apk add hare hare-doc

However, I was able to install Hare from scratch on Fedora Linux a short while ago, which was also very easy to do. If you need further instructions and Hare doesn't have a package on your system, take a look at the Hare Installation page.

In order to play with the language, I created hare-test and will be putting any of my Hare-related adventures in here.

Update:* I also created a simple Hare program for creating a file from user input: files.ha

Luckily, Hare doesn't require any complex set-up tools or build environment. Once you have Hare installed, you simply need to create a file ending with .ha and you can run a Hare program.

I created a file called rgb.ha in order to test out the random number generation and passing parameters between functions.

nano rgb.ha

Within this file, I was able to easily import a few of the standard library modules: fmt, math::random, and datetime.

With these modules, I created two functions:

1. main: This function calls the generate_rgb function and then prints out the returned values.
2. generate_rgb: This function uses the current Unix epoch time to generate a pseudo-random value and uses this value to create three more random values between 0 and 255. These three numbers represent a color in RGB format.

Note: Some syntax coloring may look odd, as Zola currently doesn't have a syntax highlighting theme for Hare. Instead, I'm using the C theme, which may not be exactly accurate when coloring the code below.

use datetime;
use fmt;
use math::random;

export fn main() void = {
    const rgb = generate_rgb();
    fmt::printfln("RGB: ({}, {}, {})", rgb[0], rgb[1], rgb[2])!;
};

fn generate_rgb() []u64 = {
    // Use the current Unix epoch time as the seed value
    let datetime = datetime::epochunix(&datetime::now());

    // Generate initial pseudo-random value
    // You must cast the datetime from int to u64
    let x = random::init(datetime: u64);

    // Generate RGB values between (0, 255) using pseudo-random init value
    let r = random::u64n(&x, 255);
    let g = random::u64n(&x, 255);
    let b = random::u64n(&x, 255);

    // Structure data as array and return
    let rgb_array: [3]u64 = [r, g, b];
    return rgb_array;
};

Once you have a Hare file written and ready to run, you simply need to run it:

hare run file.ha

You can also compile the program into an executable:

hare build -o example file.ha
./example

1. Documentation Improvements Would Help

   While I was able to piece everything together eventually, the biggest downfall right now in Hare's documentation. For such a new project, the documentation is in a great spot. However, bare specifications don't help as much as a brief examples section would.

   For example, it took me a while to figure out what the u64n function was looking for. I could tell that it took two parameters and the second was my max value (255), but couldn't figure out what the first value should be. Eventually, I inspected the random.ha file in the Hare source code and found the test suite that helped me discover that it needed an init() value in the form of &var.

2. More Basic Modules

   This is another point that comes from Hare being new and awaiting more contributions, but there are some basic functions that I would personally enjoy seeing in Hare, such as one to convert decimal (base 10) values to hexadecimal (base 16).

   If I'm feeling comfortable with my math, I may work on the list of functions I want and see if any can make it into the Hare source code.

3. Overall Thoughts

   Overall, I actually really enjoy Hare. It's not as tedious to get a project up and running as Rust, but it's also simpler and more user-friendly than learning C. I am going to continue playing with it and see if I can make anything of particular value.