roblox-cr

roblox-cr is a Crystal-to-Luau compiler for Roblox. It takes a string of Crystal code and converts it into Lua.
It's pretty unfinished, pretty undocumented, and should probably never be used for anything. It's a good project to learn how to make a source-to-source compiler though.
If you would like to contribute to or make something like this but only need the help to, consider contacting us in our Discord server.

Example (from examples/fibonacci)

Source

def fib(n : Int) : Int
  n <= 1 ? n : (fib(n - 1) + fib(n - 2))
end

puts fib 10 #=> 55

Output

function Fib(N)
  return (N <= 1 and N or Fib(N - 1) + Fib(N - 2))
end

print(Fib(10))

Installation

1. Clone the repository
2. Run make install
3. Check if everything is working by running rbxcr -h

Usage

1. Make a Roblox Crystal project using rbxcr --init
2. Write some code
3. Compile using rbxcr if you're inside of your project folder, otherwise rbxcr -D <project_dir>
4. Sync to Roblox using Rojo or another syncing plugin.

Gotchas

All identifiers are converted to PascalCase during compilation. This is due to Crystal not allowing the use of PascalCase identifiers for method names and class members. This means you need to be mindful of naming conflicts. Say you have a class, A, and you create a new instance of that class using A.new and assign it to a variable called a. The A class name will be overwritten by the a variable.
If you have any better solutions, please make a pull request.

Likely to be added

• Enums
• case-when blocks
• * (splat) operator for converting arrays to tuples

Might be added

• Macros
• Annotations

Will not be added

• loop blocks
• out keyword
• Uninitialized variables

Contributing

1. Fork it
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

Contributors

• R-unic - creator and maintainer