After a very long time, I manage to create and FMU that actually works with OpenModelica with [fmu.nim](https://github.com/mantielero/fmu.nim).
[FMU - Functional_Mock-up_Interface)](https://en.wikipedia.org/wiki/Functional_Mock-up_Interface) is a kind of file that it is used for simulation. Basically is a zip file that contains libraries (.so / .dll), .xml, . html, source code, ... and it is used to exchange simulation models accross different applications. For example, you can create a thermodynamic model in Proosis and export it to an FMU. Then you can create a control model in Matlab and integrate both models in Dymola. I created a model that simple increase a counter in 1 every second. The model is [inc.nim](https://github.com/mantielero/fmu.nim/blob/main/examples/inc/inc.nim). When you compile this with: nim c -r -d:fmu inc Run you get `inc.fmu`. Later you can [import this model in OpenModelica](https://github.com/mantielero/fmu.nim#importing-an-fmu-in-openmodelica), create a model using it and perform a simulation: It took me years (starting and stopping the project). For a pro-dev this is probably easy. But this says a lot about how good Nim is. Enabling a non-pro dev being able of doing something like this. Next step will be easy (I think). By compiling the model with `zig`, I think I will be able to create FMU's that work in Windows and Linux at the same time.
