Excellent illustration by @ivanpribec .
Ultimately “a good compiler” is what becomes critically important here. But note the practice of Fortran is such that a certain set of prevalent processors become all important because of user expectations and demands. Currently the set must include
- LFortran
- GCC/gfortran
- Intel Fortran
- Flang*.* (including Nvidia)
- Other commercial options: AMD, IBM, NAG, Cray/HPE, …
Among the above, only LFortran under the leadership of @certik and Intel in its current good workflow with free toolset and regular updates with feature enhancements and bug fixes and a commercial support infrastructure (Intel Online Service Center) appear fully focused on the immediate needs of the practitioner.
Thus the practitioners have to keep such metadata in mind as they decide to employ the features of modern Fortran.
This applies to all modern programming paradigms available increasingly with the current standard: object-oriented (OO) the subject of this thread, concurrent/parallel (DO CONCURRENT, coarrays), functional (PURE, ELEMENTAL, SIMPLE), etc.