Hello, world!

For our first program, we'll start off simple by printing "Hello, world!" to the terminal. To do so we'll need to set up a new Inko project, which we can do using the inko init command:

inko init hello
cd hello

This creates the directory hello/ containing the source files of our project, then we change the current working directory to that directory.

Once the project is created, open the file src/hello.inko and change its contents to the following:

import std.stdio (Stdout)

type async Main {
  fn async main {
    Stdout.new.print('Hello, world!')
  }
}

Then build and run the program like so:

inko build
./build/debug/hello

If all went well, the output is "Hello, world!".

Explanation

Let's explore what the program does. We first encounter the following line:

import std.stdio (Stdout)

This imports the Stdout type, used for writing text to the terminal's standard output stream. After the import we encounter the following:

type async Main {
  fn async main {

  }
}

Inko uses lightweight processes (which we'll cover separately), which are defined using the syntax type async NAME { ... }. The main process is always called "Main", and is required to define an "async" instance method called "main".

The final line writes the message to STDOUT:

Stdout.new.print('Hello, world!')

Stdout.new creates a new instance of the Stdout type, and print(...) prints the message to the standard output stream.