Variables have local scope, and are constrained to live in a block (a block
is a collection of statements enclosed by braces {}). Also,
variable shadowing is allowed.
fn main() {
// This variable lives in the main function
let long_lived_variable = 1;
// This is a block, and has a smaller scope than the main function
{
// This variable only exists in this block
let short_lived_variable = 2;
println!("inner short: {}", short_lived_variable);
// This variable *shadows* the outer one
let long_lived_variable = 5_f32;
println!("inner long: {}", long_lived_variable);
}
// End of the block
// Error! `short_lived_variable` doesn't exist in this scope
println!("outer short: {}", short_lived_variable);
// FIXME ^ Comment out this line
println!("outer long: {}", long_lived_variable);
}