Ruby 4.0, written in Rust.

Metorex runs Ruby 4.0 programs, and it exposes a method's syntax tree as objects your program can read at runtime.

example.rb

Point = Struct.new(:x, :y) do
  def +(other) = Point.new(x + other.x, y + other.y)
end

total = [Point.new(1, 2), Point.new(3, 4)].sum(Point.new(0, 0))
puts total.inspect

case total
in { x: Integer => x, y: } if y > x
  puts "y leads by #{y - x}"
end

Output

#<struct Point x=4, y=6>
y leads by 2

Ruby 4.0 syntax

Metorex reads Ruby 4.0 source with its own lexer and parser. RUBY_VERSION reports 4.0.6.

Code as objects

A method's body is available at runtime as syntax tree nodes you can inspect.

Built-in test runner

metorex --test DIR finds and runs *_test.rb, test_*.rb, and *_spec.rb files.

C extensions

Loads C extensions written against Ruby's C API.

REPL

metorex --repl starts an interactive session.

Written in Rust

The lexer, parser, and bytecode VM are written in Rust.

Metorex is in early development. Programs that run under MRI may not run under Metorex yet. Open an issue for one that fails, or send a pull request.