[Uncompetative]

In July 2012, it was announced that active development on Fortress would cease after a brief winding-down period, citing complications with using Fortress's type system on existing virtual machines.

http://en.wikipedia.org/wiki/Fortress_(programming_language)

https://blogs.oracle.com/projectfortress/

https://java.net/downloads/projectfortress/reference.pdf

I'm just putting this here as Bret Victor's link no longer works.