Move “Using objects across language boundaries” to learn section?

[awvwgk]

Beginning of this year I gave a presentation in the Fortran Object Oriented Programming Seminar Series (FOOPSS) organized by the Electronic Structure Library (ESL) initiative. The presentation is available at https://awvwgk.github.io/foopss/ with source at https://github.com/awvwgk/foopss under MIT license, it is basically one reStructuredText file.

The main topic is the export of an object oriented Fortran library to C, both for using objects instantiated in Fortran and extending Fortran base classes from C via callbacks. Finally, there is also a section on wrapping the produced C API in Python using a Foreign Function Interface (FFI) in a memory-safe way.

For a Fortran-lang minibook the presentation is rather brief and needs to be extended a bit with more elaborate discussions. Copying it over one-to-one is unlikely to yield a good learning resource. But I hope it will yield a good base for working towards resources discussed in #105.

[Mohnaa]

I can contribute on this issue.