Make sure you hace the cli installed.

Save the hello world example bellow as hello.eyg

#!/usr/bin/env eyg
{
  script: (_) -> {
    let _ = perform StandardOut("Hello, World!\n")
    0
  }
}

Update permissions chmod +x entry.eyg. Then run the script directly ./entry.eyg.

*Note:* running a script does not type check it. Type check a script using the eyg check command.

Scripts and modules

Any file containing valid source code is a module. The file containing just 5 is a module.

An EYG script is a function from the list of script arguments to a returned exit code. The type of a script function is (List(String)) -> Integer

A valid script module has a script function as a field of a record. The type of a script file/module is {script: (List(String)) -> Int, ..}.

Run a script using eyg script path/to/script.

Entryfiles

An entryfile is the first module run. It can be a valid script file and, because records are extensible, have other fields. For example a module with a "shell" field is a valid shell config.

Top-level modules may be executable and have a shebang (#!/usr/bin/env eyg).

The example below works as a script and shell config.

// entry.eyg
let tests = import "./path/to/tests.eyg"
{
  script: (arguments) -> {
    let counts = tests({})
    match !equal(counts.failed, 0) {
      True({}) -> { 0 }
      False({}) -> { 1 }
    }
  },
  shell: (_) -> {
    perform Break({})
  }
}

Start the shell with eyg shell entry.eyg Run all the tests with eyg script entry.eyg

EYG is a strongly typed replacement for bash, make and shell tools in general. Type check your whole project, application and scripts with eyg check entry.eyg