After testing and benchmarking the JSON parser from Writing a custom lexer — TOML Fortran and being quite competitive with other Fortran JSON libraries, it seemed worth to spin off this crazy idea as a separate project. Many thanks to Jacob @jacobwilliams for planting this idea!
Jonquil (named after the flower) is available with fpm, meson and CMake and brings all the features available for TOML to JSON land (name established in the TOML specs at TOML: English v1.0.0). In fact it provides a seamless intercompatibility when working with the data structures of either library and allows to mix and match them freely. One key strength of Jonquil is that the data structures are not using any pointer components, but only allocatables, making them safe to work with, easy to (deep-)copy and simple to delete without special care or extra finalization.
To be honest, it is kind of a silly idea this project is based on. The jonquil module basically reexports the whole TOML Fortran API, but renames it according to the JSON conventions:
Since those are still the same types and procedures as in TOML Fortran, they look and feel different, but provide all the same functionality. Meaning with Jonquil you get a nice different flavor of TOML Fortran and maximum compatibility for free.