std::any::Any
Trait std::any::Any
pub trait Any: 'static {
fn get_type_id(&self) -> TypeId;
}
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-
Required Methods
fn get_type_id(&self) -> TypeId
Gets the TypeId of self.
Examples
#![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);
} Methods
impl Any + 'static
[src]
fn is<T>(&self) -> bool where
T: Any,
T: Any,
Returns true if the boxed type is the same as T.
Examples
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());
} fn downcast_ref<T>(&self) -> Option<&T> where
T: Any,
T: Any,
Returns some reference to the boxed value if it is of type T, or None if it isn't.
Examples
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());
} fn downcast_mut<T>(&mut self) -> Option<&mut T> where
T: Any,
T: Any,
Returns some mutable reference to the boxed value if it is of type T, or None if it isn't.
Examples
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");
}
impl Any + 'static + Send
[src]
fn is<T>(&self) -> bool where
T: Any,
T: Any,
Forwards to the method defined on the type Any.
Examples
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());
} fn downcast_ref<T>(&self) -> Option<&T> where
T: Any,
T: Any,
Forwards to the method defined on the type Any.
Examples
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());
} fn downcast_mut<T>(&mut self) -> Option<&mut T> where
T: Any,
T: Any,
Forwards to the method defined on the type Any.
Examples
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");
} Trait Implementations
impl Debug for Any + 'static
[src]
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
Formats the value using the given formatter.
impl Debug for Any + 'static + Send
[src]
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
Formats the value using the given formatter.
Implementors
impl<T> Any for T where
T: 'static + ?Sized,
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/any/trait.Any.html
