Forward declaration of types in C++ is very limited. You can say `class T;` and even forward declare a function that takes a pointer to the type `foo(T*)` but not much more. You cannot forward declare class methods, etc. Regarding `*.h` and `*.c` files nothing prevent you from having header file `foo_h.nim` in addition to `foo.nim`. One can even simulate include guards with `const FOO_H=true` in `foo_h.nim` and `when defined(FOO_H):` in `foo.nim`.
Regarding the Nim's file scope, I am not sure I understand. Symbols can be exported from modules to the global scope. I know that all these solutions are suboptimal, but they worked in C/C++ land for decades. \--Leo| ---|---
