Category talk:Egison

What is this page?

The Egison programming language linked here is this one. The language shown on that page, and in the accompanying thesis, is ML-like, with syntax like so

def twinPrimes := matchAll primes as list integer with
  | _ ++ $p :: #(p + 2) :: _ -> (p, p + 2)

But this category page, and all of the linked challenges, seem to be using a Lisp-style language that doesn't remotely resemble the one on the Egison website. Is there a second language called "Egison"? Did Egison used to be Lisp-like, and this page is just stale? I'm quite puzzled.