A trait refers to a group of methods defined for a specific type. Traits are incredible as they provide an abstraction for functionality and logic that can be shared between multiple types.
Traits support concrete and abstract methods, as we will see in this article.
Rust Define Trait
To define a trait in Rust, we use the trait keyword, followed by the trait’s name and body. The trait body can contain either concrete or abstract method.
The syntax is as shown:
fnabs_method(&self);
fncon_method(&self) {
// function body
}
}
Note that a trait method includes the &self parameter. This must be the first parameter in the method, and other parameters must be provided after.
fn description(&self) -> String;
fn mileage(&self) -> f64;
}
In the code above, we define a strait called Info that contains abstract methods. A car object can use the methods above. However, since the method of description and mileage values can differ depending on the car, the logic has to be applied distinctly.
Rust Implement Trait
After defining a trait, we can need to implement it. The syntax for trait method implementation is similar to a struct method.
Consider the example below:
fndescription(&self) ->String;
fnmileage(&self) ->f64;
}
structVehicle {
model: String,
manufacturer: String,
price: i32
}
impl Info for Vehicle {
fndescription(&self) ->String{
returnformat!("Model: {}, Manufacturer: {}, Price: {}", self.model, self.manufacturer, self.price);
}
fnmileage(&self) ->f64 {
return10000.33;
}
}
In the above example, we define a struct that holds information for a vehicle. We can then implement methods, as shown above.
In the main function, we can have instances for the Vehicle structs as shown:
let car = Vehicle{
model: "Camry".to_string(),
manufacturer: "Toyota".to_string(),
price: 25295
};
let motorcycle = Vehicle {
model: "V-Max".to_string(),
manufacturer: "Yamaha".to_string(),
price: 27999
};
}
In the code above, we define two instances of the Vehicle struct with the properties implemented differently.
Calling Trait Methods
Once we have implemented the methods for a trait, we can call the method using the dot notation as shown:
This should return:
Conclusion
This guide provides the fundamentals for working with traits in the Rust language. Consider the documentation to learn more.
