Ratfor ("Rational Fortran") is a preprocessor for Fortran that provides modern control structures to replace Fortran's GOTOs and statement numbers. It first appeared in the book "Software Tools" (Kernighan and Plauger, 1976).

Ratfor is itself written in standard Fortran, and inasmuch as its own translation to Fortran is available, it can be ported to any Fortran system, and surely has been.

There's more about Ratfor at http://sepwww.stanford.edu/software/ratfor.html.