Ruby, or is it?

gistfile1.rb

Factorial = (n) {
  (y,f) { y.(f).(n) }.(
    (le) {
      (f) { f.(f) }.(
        (f) {
          le.(->(x) { f.(f).(x) })
        })
    },
    (recurse) {
      (n) { (n==0) ? 1 : n * recurse.(n-1) }
    })
  }
p Factorial.(5)