Adding crates

Third party libraries are called Crates (and are available from https://crates.io). To add a crate, for example Serde, add this line to Cargo.toml after the [dependencies] line:

serde = "1.0.0"

You’ll still need to import the individual parts of the crate you want to use, for example:

use serde::json::Serialize;

::Foo means import just Foo

::{Foo, Bar} means import Foo and Bar

::* means import everything in the module.

You can rename when importing:

use example::Foo as Bar;

Most of the massive crates have a prelude module that you should import, i.e.

use chrono::prelude::*

Features

Some crates have optional features, often these include macros or provide interop with other crates:

serde = "1.0.0" can also be written as serde = { version = "1.0.0" }. To include a feature this gets expanded to serde = { version = "1.0", features = ["derive"] }.

Some crates will have features that you almost always want: