├── Cargo.lock ├── Cargo.toml ├── src/ │ ├── lib.rs │ ├── main.rs │ ├── some_dir │ ├── some_file.rs Assume in some_file.rs we have: pub fn foo() { // ... } How can I call this function in lib.rs?

#[path] is unnecessary if the directory structure mimics the intended module structure: mod some_dir { pub mod some_file; // must be `pub` to be visible outside this module } // how you call it: some_dir::some_file::foo();

For that example, you could specify the module file path explicitly when declaring the module in lib.rs: #[path = "some_dir/some_file.rs"] mod some_mod; pub fn run() { some_mod::foo(); }

Have a look at my cheat sheet: [image] Cargo package structure cheat sheet announcements I made a summary of all the file name conventions that cargo recognizes: [rust-package-structure-cheatsheet] Blue are names of your choosing, black names must be used verbatim. …

I understand the hierarchy, but the difficulty I find in cargo is how to call functions of different files, 'import' modules of other files and use them, in other words, how the files interact with each other in hierarchy. Thanks anyways.

[image] 109149: how to call functions of different files Start by thinking about this not as "calling functions of different files" but "calling functions of different modules". [image] 109149: 'import' modules of other files Again, you import (use) modules, not files. The tree of mod…

Don't know if this will help or not, but there seem to be 2 things about the module system that tend to trip people up when coming to Rust from other languages: There is a file hierarchy and a module hierarchy. Both can be any shape you want, but things will usually be easiest for you if they are…

[image] trentj: There is a file hierarchy and a module hierarchy. I agree. [image] trentj: Both can be any shape you want, but things will usually be easiest for you if they are the same shape. I disagree with both points. :slight_smile: They cannot be any shape you want. Without usi…

#[path] is part of what I'm talking about when I say "any shape you want", yes. (Along with being able to specify the crate root in Cargo.toml.) It's not mentioned in the book, but everybody seems to know about it anyway, so I wouldn't call it "obscure". Of all the people who post in here confused a…

[image] trentj: Of all the people who post in here confused about modules, probably 75% of them¹ already know about it and have used it to further confuse themselves. Exactly, I think there's some selection bias going on here... those who know about [#path] are confused about the module syste…

Understand packages, crates and path

help

AndreKR October 16, 2020, 12:35pm 4

Have a look at my cheat sheet:

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Rust File Organization, imports, etc help	18	14330	December 18, 2023
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How to use a module from another directory? help	2	650	April 30, 2025

Understand packages, crates and path

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