How to use multiple subdirectories inside "src"?

help
1

Let's say that I have the following structure in my project:

Cargo.toml
src
  | main.rs
  | commons.rs
  | messages
    |help.rs
    | usage.rs

Actually that's the true structure but I have more files/dirs. So I want to use the "help.rs" and "usage.rs" in both the "main.rs" and "commons.rs" files. When trying to use "commons.rs" in "main.rs", I can just use: mod commons because they are in the same directory and it works. I thought about using: mod messages::help and mod messages::usage to import them but it doesn't work as expected. Any ideas?

1 Like
2

You only need the mod declaration in one place, from the parent module, and then other places can use the path to that module. I think this chapter of the book will help you:

https://doc.rust-lang.org/book/ch07-00-managing-growing-projects-with-packages-crates-and-modules.html

3

The book doesn't refer about how to use subdirectories (unless I'm blind) inside "src" however. Luckily I was able to find how to do it thanks to this video. Thanks a lot for your time and have an amazing day

4

7.5 in particular does talk about file and directory layout.

5

It does but again, it doesn't contain info about how to create subdirectories and that you need to have a "mod.rs" file in the subdirectory and you also have to include any module publicly in this file. If I remember correctly, the book doesn't specify that you only have to declare a module only in the root source file and you don't have to do it in any other file in the directory. The book can indeed improve and I will probably contribute one time when I have free time

1 Like
6

True, this seems like a pretty big omission.

7

Ah, I missed that about your original example. You can use either messages.rs or messages/mod.rs, and that does need mod declarations for the submodules in messages/.

1 Like
8

I don't blame them of course. I really appreciate the fact that that they spend their free time for the community. I will probably contribute when I have free time

9

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