Chemical JSON support in xtb

[awvwgk]

I implemented chemical JSON support in the input library of xtb and other related projects like dftd4 or s-dftd3. For xtb this means chemical JSON is a valid input format for the geometry and outputs for example from geometry optimizations can be produced in the same JSON format as well.

I would be curious whether there are any implementations besides Avogadro which support chemical JSON. Or more general which compiles packages have native support for standardized JSON formats like pymatgen, QCSchema or chemical JSON.

[ghutchis]

Open Babel now has support for CJSON. It would be fairly easy to add pymatgen and QCSchema if they've become more stable now.

I know that cclib has support for CJSON and I think QCSchema as well.

[berquist]

cclib

For CJSON, there is an old reader/writer that is likely not up to date.

For QCSchema, there is most of an implementation against the QCSchema repo (not the canonical QCElemental model(s)) but it hasn't been merged yet.

[ghutchis]

I can add some tests to avogadrolibs both for cclib and mctc-lib in the io section. I've been building up a set or more example files, both for unit tests and fuzz testing.

I'll add more example files and unit / roundtrip tests to this repo as well. It might take a few weeks since I have some other work (bureaucracy) to finish this month.