Myst

A structured, dynamic, general-purpose language.

deftype List
  def contains(element)
    each(&fn
      ->(<element>) { break true }
      ->(_)         { false }
    end)
  end
end

[1, 2, 3].contains(2) #=> true

Some of the high-level features include:

• Pattern-matching everywhere. Assignments, method parameters, rescue clauses, etc.
• Multiple-clause functions. All functions can define multiple clauses to adapt functionality based on inputs.
• Value interpolations. Interpolate any value anywhere (even in method parameters) with the <> syntax.
• Soft typing. Optional type annotations help control functionality without cluttering your code with conditionals.
• Raise anything. Any value can be raised as an Exception and pattern matched in a rescue block.

Installation

NOTE: Due to Crystal's current limitations with compiling on Windows, Myst only works on macOS and Linux systems.

macOS

The distribution of Myst is currently maintained through a custom homebrew tap at https://github.com/myst-lang/homebrew-tap.

Installation is pretty simple - you don't even have to add the tap if you don't want to:

# If you're okay with adding the tap:
brew tap myst-lang/tap
brew install myst-lang

# Or, if you would rather not add the tap:
brew install myst-lang/tap/myst-lang

And that's it! You should now have a myst executable in your $PATH that can be used anywhere.

Linux/without brew

There is currently no native package manager solution for Myst on linux systems. Instead, you'll need to build and install the binary manually. Luckily it's not too complicated.

Note that you'll need crystal installed for the build to succeed. This dependency is automatically managed on macOS. To install crystal, follow these steps :

# apt-get install dirmngr
# curl https://dist.crystal-lang.org/apt/setup.sh | bash
# apt-get install crystal

Now, install myst. cd to your prefered root dir, then :

First, download the latest release or the development (master) reposirtory :

$ wget https://github.com/myst-lang/myst/archive/v0.1.0.tar.gz
or
$ wget https://github.com/myst-lang/myst/archive/master.tar.gz

then untar it somewhere and go to the extracted directory

```
$ tar xvf v0.1.0.tar.gz
or 
$ tar xvf master.tar.gz

$ cd myst-0.1.0/
$ shards build
```

This will give you a bin folder with a myst executable inside of it. Now, there are two options:

1. Simply add the bin/ directory to your PATH environment variable at the end of your ~/.bash_profile file :

    export PATH="$PATH:/path/to/bin/myst"
   

Then, update your current profile using the source ~/.bashrc command.

2. The second option is to create a symlink from /usr/local/bin or some other folder on your $PATH to the bin folder that shards build generated.

ln -s /path/to/bin/myst /usr/local/bin/myst

3. The third option is to move the entire Myst folder to a folder on your $PATH. The executable needs to be in a folder that is a sibling to the stdlib folder at the root of this project. For example:

root
|- bin
|  |- myst
|- stdlib
|  |- enumerable.mt
|  |- ...
|  |- prelude.mt

As long as this structure is maintained, the executable should work as expected. Otherwise, you will see an error along the lines of "No file or directory stlib/prelude.mt". Full instructions TBD.

Help with improving these installation instructions, making pre-built binaries, and/or managing releases would be greatly appreciated :)

Get Involved

If you have an idea for a new feature or find a bug in Myst, please file an issue for it!. Using the language and finding bugs are the best ways to help Myst improve. Any and all help here is appreciated, even if that just means trying out the language for a day.

If you just want to get involved in the community, come hang out in our Discord server!. We're a pretty small community, so there's plenty of room for anyone that would like to hang out, even if it has nothing to do with Myst!

When I can, I try to label issues with help wanted or good first issue. help wanted is for issues that I'd really like external input on, while good first issue is for issues that can be implemented without too much knowledge of how the lexer/parser/interpreter works. On these issues, I try to explain as much as possible about what the solution looks like, including files that will need editing and/or methods that need implementing/changing. I hope that helps!

If you'd like to tackle something, but don't know where to start, please let me know! I'd love to help you get involved, so feel free to ask in the discord server or message me directly (faulty#7958 on discord, or email also works) and I'll do my best to get you up and running.

The Basics

If you would like to contribute to Myst's development, just:

1. Fork it (https://github.com/myst-lang/myst/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request (https://github.com/myst-lang/myst/pull/new)

Owning an issue

If you have a specific issue that you'd like to tackle, be sure to add a comment saying you're working on it so that everyone is aware! (currently, github doesn't allow for assigning issues to new contributers :/)

Also, "ownership" is not binding. It's just a way of saying "hey, I think I can work on this!". If you get stuck or need help moving forward, feel free to ask for help either on the issue itself, or in the discord server.

Most importantly, don't feel bad if you bite off more than you can chew. Issues can easily end up being far more complex than they appear at the start, especially on a project of this size. But don't give up! It's always hard to get started on an existing project, but I want to help and make it as easy as possible wherever I can!