How to use multiple levels of module?

suppose that we have a module hierarchy of Foo.Bar.XX, and Foo.YY
in the XX module, how can I use YY module?
I tried these two, do not work
using …/…YY
using …YY

Can you please write some code with the modules so that we can try answer the question properly?

This test code works, but the same way do not work in my project…

module C                                                                                                              
 end                                                                                                                   
                                                                                                                       
 module A                                                                                                              
 module B                                                                                                              
 using ....C                                                                                                           
 end                                                                                                                   
 end         
1 Like

Then the issue is somewhere else in your project? Try to comment out the code until you get something that works. The syntax is correct, you can do

using C

or

using ....C

in this case because the module C is at the top level (i.e. Main.C).

Thanks, I’ll just use the Main.C approach for now. It works.