[gspr]

But interfacing with Fortran from other languages is easy (well, barring some compiler assumptions that everyone seems to be making anyway). Why not leverage the general purpose strength of languages like Rust or C++ or Python (or even C), while still retaining access to the vast trove of numerical Fortran libraries?

(Not that I'm judging, people should use whatever language they prefer).

[ryl00]

That's what tends to happen, at least in the code I've worked on. C/C++ for the bits that need to "talk" to the OS, python/perl/bash for scripting purposes, and Fortran for the number-crunching core.