From the use-cases I've seen, OOP didn't make a massive difference. Many of the ideas from OOP were possible before, e.g. abstraction with modules and derived types (essentially C structs) from Fortran 90/95. Others, like polymorphism felt a bit bolted on and haven't gained widespread usage.
As for a self-hosting compiler, I'm not aware of one, although it's something I'd be interested in having a go at. I've written a regex engine in Fortran before, I just haven't had the time to sit down with the Fortran standard and a textbook on compiler design (I'm a physicist by trait, so I've not been taught this stuff formally).
As for a self-hosting compiler, I'm not aware of one, although it's something I'd be interested in having a go at. I've written a regex engine in Fortran before, I just haven't had the time to sit down with the Fortran standard and a textbook on compiler design (I'm a physicist by trait, so I've not been taught this stuff formally).