From the site:

What is Frege?

Winner of the JavaOne Emerging Languages Bowl 2015, 2016, 2017

Frege is a Haskell for the JVM.

Like any Haskell, it is purely functional, enjoys a strong static type system with global type inference and non-strict - also known as lazy - evaluation.

Frege compiles to Java, runs on the JVM, and uses any Java library you want. It can be used inside any Java project.

Come on, Frege is the greatest logician since Aristotle, not some JVM port.