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Use Declarations in Rust Programming
Use Declarations in Rust are used to bind a full path to a new name. It can be very helpful in cases where the full path is a bit long to write and invoke.
In normal cases, we were used to doing something like this:
use crate::deeply::nested::{
my_function,
AndATraitType
};
fn main() {
my_function();
}We invoked the use declaration function by the name of the function my_function. Use declaration also allows us to bind the full path to a new name of our choice.
Example
Consider the example shown below:
// Bind the `deeply::nested::function` path to `my_function`.
use deeply::nested::function as my_function;
fn function() {
println!("called `function()`");
}
mod deeply {
pub mod nested {
pub fn function() {
println!("called `deeply::nested::function()`");
}
}
}
fn main() {
// Easier access to `deeply::nested::function`
my_function();
println!("Entering block");
{
// This is equivalent to `use deeply::nested::function as function`.
// This `function()` will shadow the outer one.
use crate::deeply::nested::function;
// `use` bindings have a local scope. In this case, the
// shadowing of `function()` is only in this block.
function();
println!("Exiting block");
}
function();
}Output
called `deeply::nested::function()` Entering block called `deeply::nested::function()` Exiting block called `function()
Updated on: 05-Apr-2021
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