jasonleonhard/leonhard_lib

Create your own rust library and import it within the module system.

If you would prefer to reuse this library in other projects I recommend checking it into git and tossing it up on github. If you only will use this library internal please scroll down to that section.

Below are instructions how to build an external "library"

cargo new leonhard_lib --lib     # your new library name
cdd                          # cd into newest created folder

src/lib.rs is where you add this code:

pub mod file_io {
    // #[allow(dead_code)]
    pub fn some_function() {
        println!("# some_function called");
    }
}

In order for the module to be accessible it must be pub. Same goes for the method within the module.

Cargo.toml

Requires the absolute or relative path to the dependency, in this case the library called leonhard_lib.

[dependencies]
leonhard_lib = {path = "../leonhard_lib"}

Because all of your rust projects should live at the top level ~/code/rust/ you can then easily use relative paths, reuse a ton of code and be setup nicely for git and a github repository for your library. And with that our rather simple library is ready for use in some project

cargo new create_use_library # your project folder name
cdd                          # cd into newest created folder

main.rs

use leonhard_lib::file_io;

fn main() {
    file_io::some_function();
}

Here we import the library called leonhard_lib but only the module file_io, so if there are more modules they are intentionally not accessible for now.

Calling file_io::some_function(); to execute when the program runs.

Run

To both build and run you can use:

cargo run

Build, Test, Run

cargo test; cargo run;

Note that you do not need to navigate down the tree to your library folder leonhard_lib, when build or run occur the library will be complied. Thus adding more methods to lib.rs you save some navigation effort too.

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Internal "library"

Below are instructions how to use a library for just for one project, aka not reusing code in multiple projects, just this one:

cargo new create_use_library # your project folder name
cdd                          # cd into newest created folder
cd src                       # where your library folder lives
cargo new leonhard_lib --lib     # your new library name

src/lib.rs is where you add this code:

pub mod file_io {
    // #[allow(dead_code)]
    pub fn some_function() {
        println!("# some_function called");
    }
}

In order for the module to be accessible it must be pub. Same goes for the method within the module.

Cargo.toml

Requires the absolute or relative path to the dependency, in this case the library called leonhard_lib.

main.rs

use leonhard_lib::file_io;

fn main() {
    file_io::some_function();
}

Here we import the library called leonhard_lib but only the module file_io, so if there are more modules they are intentionally not accessible for now.

Calling file_io::some_function(); to execute when the program runs.

Run

To both build and run you can use:

cargo run

Build, Test, Run

cargo test; cargo run;

Note that you do not need to navigate down the tree to your library folder leonhard_lib, when build or run occur the library will be complied. Thus adding more methods to lib.rs you save some navigation effort too.

This however is not the case for cargo test from the top level. That will not run your module level unit tests (aka leonhard_lib) has some tests that are ran if you instead run cargo test --package leonhard_lib which will run only the tests from that package, from the top level without navigating down.