Well has not really to be Nim already, simple would be enough 
I got recently the request to add libadwaita to the Nim gintro bindings:
https://github.com/StefanSalewski/gintro/issues/120
Well, libadwaita seems to be the GTK4 port of libhandy. I added libhandy by request some time ago, so maybe I should not refuse to add libadwaita.
Indeed I added bindings generation for libwaita yesterday, but generally I add also an example application.
For libhandy I ported a simple numeric keypad from a Python example, so that users have a basic start.
But for libadwaita? There is one larger example included in the C sources, but porting that one to Nim may take me some days, as I do not really understand all details. (I have never used libadwaita before, and do not really intent to use it in near future.)
I was not too lazy, I did a basic start like
cp -r ~/libadwaita/examples/ /tmp/adw
cd /tmp/adw
gcc -Wall adwaita-demo.c adw-demo-window.c adw-flap-demo-window.c adw-view-switcher-demo-window.c adw-demo-preferences-window.c -o adw `pkg-config --cflags --libs gtk4 libadwaita-1`
But of course that will not work as the example uses resources. So next step would be how to remember how one compiles resources manually and ask the Nim compiler to add it to the executable. Or I would have to modify the source code to load ui files directly. May be possible somehow.
Well of course the meson build does all that for me during install, but for porting I would have to understand the single steps.