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Installation
============

Asteroid is available from the PyPI project website
`pypi.org/project/asteroid-lang <https://pypi.org/project/asteroid-lang>`_
and is installed using::

    $ pip install asteroid-lang

The should work on Unix-like and Windows systems,
though you may have to use `pip3` or some other variation.

  Don't forget to add the `bin` directory where `pip` installs programs
  to your `PATH` variable.

In addition to installing Asteroid directly on your machine,
there is also a cloud-based Linux virtual machine that is completely
set up with an Asteroid environment and can be accessed at
`Repl.it <https://repl.it/@lutzhamel/asteroid#README.md>`_.

Running the Asteroid Interpreter
================================

You can now run the interpreter from the command line by simply typing `asteroid`.
This will work on both Windows and Unix-like systems as long as you followed the instructions above.
To run asteroid on Unix-like systems and on our virtual machine,
::

    $ cat hello.ast
    -- the obligatory hello world program

    load system io.

    io @println "Hello, World!".

    $ asteroid hello.ast
    Hello, World!
    $

On Windows 10 the same thing looks like this,
::

    C:\> type hello.ast
    -- the obligatory hello world program

    load system io.

    io @println "Hello, World!".

    C:\> asteroid hello.ast
    Hello, World!
    C:\>


As you can see, once you have Asteroid installed on your system you can execute an
Asteroid program by typing::

    asteroid [flags] <program file>

at the command prompt.  Asteroid also supports an interactive mode::

    $ asteroid
    Asteroid Version 1.0.0
    Run "asteroid -h" for help
    Press CTRL+D to exit
    > load system io.
    > io @println "Hello, World!".
    Hello, World!
    >