A type to emulate dynamic typing.
Most types implement Any
. However, any type which contains a non-'static
reference does not.
See the module-level documentation for more details.
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static
Gets the TypeId
of self
.
#![feature(get_type_id)]
use std::any::{Any, TypeId};
fn is_string(s: &Any) -> bool {
TypeId::of::<String>() == s.get_type_id()
}
fn main() {
assert_eq!(is_string(&0), false);
assert_eq!(is_string(&"cookie monster".to_string()), true);
}
Returns true
if the boxed type is the same as T
.
use std::any::Any;
fn is_string(s: &Any) {
if s.is::<String>() {
println!("It's a string!");
} else {
println!("Not a string...");
}
}
fn main() {
is_string(&0);
is_string(&"cookie monster".to_string());
}
Returns some reference to the boxed value if it is of type T
, or
None
if it isn't.
use std::any::Any;
fn print_if_string(s: &Any) {
if let Some(string) = s.downcast_ref::<String>() {
println!("It's a string({}): '{}'", string.len(), string);
} else {
println!("Not a string...");
}
}
fn main() {
print_if_string(&0);
print_if_string(&"cookie monster".to_string());
}
Returns some mutable reference to the boxed value if it is of type T
, or
None
if it isn't.
use std::any::Any;
fn modify_if_u32(s: &mut Any) {
if let Some(num) = s.downcast_mut::<u32>() {
*num = 42;
}
}
fn main() {
let mut x = 10u32;
let mut s = "starlord".to_string();
modify_if_u32(&mut x);
modify_if_u32(&mut s);
assert_eq!(x, 42);
assert_eq!(&s, "starlord");
}
Forwards to the method defined on the type Any
.
use std::any::Any;
fn is_string(s: &(Any + Send)) {
if s.is::<String>() {
println!("It's a string!");
} else {
println!("Not a string...");
}
}
fn main() {
is_string(&0);
is_string(&"cookie monster".to_string());
}
Forwards to the method defined on the type Any
.
use std::any::Any;
fn print_if_string(s: &(Any + Send)) {
if let Some(string) = s.downcast_ref::<String>() {
println!("It's a string({}): '{}'", string.len(), string);
} else {
println!("Not a string...");
}
}
fn main() {
print_if_string(&0);
print_if_string(&"cookie monster".to_string());
}
Forwards to the method defined on the type Any
.
use std::any::Any;
fn modify_if_u32(s: &mut (Any + Send)) {
if let Some(num) = s.downcast_mut::<u32>() {
*num = 42;
}
}
fn main() {
let mut x = 10u32;
let mut s = "starlord".to_string();
modify_if_u32(&mut x);
modify_if_u32(&mut s);
assert_eq!(x, 42);
assert_eq!(&s, "starlord");
}
pub fn is<T>(&self) -> bool where T: Any, | 1.28.0 [src] |
Forwards to the method defined on the type Any
.
use std::any::Any;
fn is_string(s: &(Any + Send + Sync)) {
if s.is::<String>() {
println!("It's a string!");
} else {
println!("Not a string...");
}
}
fn main() {
is_string(&0);
is_string(&"cookie monster".to_string());
}
Forwards to the method defined on the type Any
.
use std::any::Any;
fn print_if_string(s: &(Any + Send + Sync)) {
if let Some(string) = s.downcast_ref::<String>() {
println!("It's a string({}): '{}'", string.len(), string);
} else {
println!("Not a string...");
}
}
fn main() {
print_if_string(&0);
print_if_string(&"cookie monster".to_string());
}
Forwards to the method defined on the type Any
.
use std::any::Any;
fn modify_if_u32(s: &mut (Any + Send + Sync)) {
if let Some(num) = s.downcast_mut::<u32>() {
*num = 42;
}
}
fn main() {
let mut x = 10u32;
let mut s = "starlord".to_string();
modify_if_u32(&mut x);
modify_if_u32(&mut s);
assert_eq!(x, 42);
assert_eq!(&s, "starlord");
}
Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
impl<T> Any for T where T: 'static + ?Sized, | |