938 B
938 B
Variables.
Definition.
Immutable.
Use the let
keyword to start declaration. Types are specified after the variable name.
let x: i32 = 10;
Type definition is optional, so you can drop it. I suggest specifying the type for global/class/etc variables, but dropping it in local scope like functions.
let x = "This is &str"; // Type is detected automatically: &str.
Mutable.
Add mut
keyword after let
.
let mut x: i32 = 10;
x = 12;
Constants.
To declare constant, use the const
keyword instead of let
. Constant values always require type definition.
const NUMBER: i32 = 10;
Shadowing.
You can redefine a variable with the same name but with a different type. This is useful if you cast something, but want to keep the same variable name. To do this, just declare the variable again.
let x: &str = "&str"; // &str.
let x: i32 = 10; // i32.