rebo-lang

Rebo is a dynamically typed interpreted programming language. It is a work in progress.

I love tinkering around with programming languages trying to understand the techniques used to implement them. I have been working on a number of projects in little languages exploring these techniques. Strangely enough, other than for Lisp, all of my efforts have been directed at statically typed languages. I stumbled upon Oak and was really impressed with what the author has achieved using a simple language and philosophy. I decided to try my hand at a dynamically typed language.

Primary influences:

• Oak
• TypeScript running on Deno
• Elm
• Kotlin

Rebo itself has the following features:

• Indent based syntax,
• Dynamically typed,
• Local and remote packages,
• First class functions,
• Pattern matching,
• Unit, boolean, char, integer, float, string, function, sequence and record types, and
• Iteration through (tail) recursion.

The interpreter is written in Zig.

It is super early so, for now, star the project or periodically check back for updates.

Examples

The first 1,000 prime numbers:

let { filter, range } = import("std")

let prime?(n) {
  let loop(i = 2) =
    if i * i > n -> true
     | n % i == 0 -> false
     | loop(i + 1)

  if n < 2 -> false
   | loop()
}

let primes(n) =
  range(2, n)
    |> filter(prime?)

println("The first 1000 prime numbers are: ", primes(1000))

The following is the REST version of hello world.

let HTTP = import("http")

let server = HTTP.Server()
server.route("/hello/:name") <| fn(params) =
    fn(req, end) =
      if req.method
      | "GET" -> end({
            status: 200,
            body: "Hello, " + params.name ? "World" + "!"
        })
      | _ -> end(HTTP.MethodNotAllowed)

server.start(9999)

Installation

I have created an installation script that will install Rebo on any platform that has a bash shell. The installation script is available at https://raw.githubusercontent.com/graeme-lockley/rebo-lang/main/tasks/install.sh. To install Rebo, execute the following command:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/graeme-lockley/rebo-lang/main/tasks/install.sh)" -- ~/rebo

The installation script will install Rebo in the directory ~/rebo. If you would like to install Rebo in a different directory, replace ~/rebo with the directory where you would like the installation to be placed.

Note that you will need to manually add the Rebo binary to your path. In the example above that would be

export PATH=$PATH:~/rebo/bin

See also

• Where does the name "Rebo" come from? I am an annoying Star Wars fan and it is a reference to the Max Rebo Band from Return of the Jedi.
• I have embedded Zigline into the interpreter to provide a REPL. Using Zigline is a bit of a hack at the moment but it works until Zig has stablised its package management and the build tools it will have to do.

Languages of interest

This list is of languages that I am keeping an eye on - they are interesting and I am curious to see how they evolve.

• Gleam is a strongly typed functional language that compiles to Erlang.