I saw a project a couple weeks back which allows writing and running Crystal methods inline inside a Ruby file. It’s a neat project, and I don’t want to take away from it but something in the README example looked off to me. require 'crystalruby' require 'benchmark' module Fibonnaci crystalize [n: :int32] => :int32 def fib_cr(n) a = 0 b = 1 n.times { a, b = b, a + b } a end module_function def fib