Struct swc_common::sync::Lazy [−][src]
pub struct Lazy<T, F = fn() -> T> { /* fields omitted */ }
Expand description
A value which is initialized on the first access.
Example
use once_cell::unsync::Lazy;
let lazy: Lazy<i32> = Lazy::new(|| {
println!("initializing");
92
});
println!("ready");
println!("{}", *lazy);
println!("{}", *lazy);
// Prints:
// ready
// initializing
// 92
// 92
Implementations
Creates a new lazy value with the given initializing function.
Example
use once_cell::unsync::Lazy;
let hello = "Hello, World!".to_string();
let lazy = Lazy::new(|| hello.to_uppercase());
assert_eq!(&*lazy, "HELLO, WORLD!");
Consumes this Lazy
returning the stored value.
Returns Ok(value)
if Lazy
is initialized and Err(f)
otherwise.
Forces the evaluation of this lazy value and returns a reference to the result.
This is equivalent to the Deref
impl, but is explicit.
Example
use once_cell::unsync::Lazy;
let lazy = Lazy::new(|| 92);
assert_eq!(Lazy::force(&lazy), &92);
assert_eq!(&*lazy, &92);
Trait Implementations
Auto Trait Implementations
impl<T, F> UnwindSafe for Lazy<T, F> where
F: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more