Roy

Roy is a small functional language that compiles to JavaScript. It has a few main features:

• Damas-Hindley-Milner type inference
• Whitespace significant syntax
• Compile-time meta-programming
• Simple tagged unions
• Pattern matching
• Structural typing
• Monad syntax
• Not-horrible JS output

Usage

To compile:

make deps
make

To enter a REPL:

./roy

To compile and run a .roy file:

./roy -r examples/helloworld.roy

To compile a .roy file to .js:

./roy examples/helloworld.roy
cat examples/helloworld.js

Example

Input (test.roy):

let addTwo n =
    n + 2

console.log (addTwo 40)

Output (test.js):

var addTwo = function(n) {
return n + 2;
}
console.log(addTwo(40))

Calling addTwo "test" will result in a compile-time error.

See the examples directory for more.

TODO

• Mutable types
• Types across modules
• Allow explicit types that have type parameters
• Standard libary
• Tail recursion