Write and run a program

Save this program as hello.hy:

public class Program {
    public static int Main(string[] args) {
        string name = "World";
        if (args.Length > 0) { name = args[0]; }
        System.Console.WriteLine("Hello, " + name);
        return 0;
    }
}

hy compile hello.hy -o hello
chmod +x hello
./hello Hydrogen

For repeat runs, execute ./hello directly. The release compiler produces native executables; it does not have an interpreted run command.

Entry point and arguments

Main must be a static class method returning int or void. It accepts no parameters or one string[] parameter. Arguments exclude the executable name; an integer result becomes the process exit status.

Array access is checked, so test args.Length before indexing. UEFI output is different: an EFI application is booted by firmware, not run from Linux.