rust-git | yeah | Awesome List library

First things first, go back and re-read The Rust Programming Language's chapter on "Packages, Crates, and Modules". This discusses several fundamental concepts that are vital for understanding.

Why can I not clone a git project, add a main.rs and import one of the structs?

To me, this feels like the same question as "why can't I reach into another human, grab their lungs, and then use them to breathe"? You simply cannot download some arbitrary Rust library and start pulling random files out of it and expect them to work.

Specifically in your case, all libraries have a lib.rs that is the crate root. The crate root tends to have many common definitions that are needed by the rest of the code and imports all the submodules. When you create a main.rs and declare the modules from the library as your own, your main.rs becomes the crate root, but it doesn't define all the things that the library needs. This causes the code to fail to compile.

Instead, just use the crate as a library, as it's intended.

The easiest thing to do create a new Cargo project and add the crate as a dependency to your Cargo.toml. The gitlab crate is already distributed on crates.io, so you just add the version number: