Any in core::any - Rust
Description: A trait to emulate dynamic typing.
Keywords: rust, rustlang, rust-lang, Any

# Trait core::any::Any
1.0.0[−][src]

    pub trait Any: 'static {
        fn type_id(&self) -> TypeId;
    }

Expand description

A trait 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 type_id(&self) -> TypeId

1.34.0[src]

Gets the `TypeId` of `self`.

# Examples

    use std::any::{Any, TypeId};

    fn is_string(s: &dyn Any) -> bool {
        TypeId::of::<String>() == s.type_id()
    }

    assert_eq!(is_string(&0), false);
    assert_eq!(is_string(&"cookie monster".to_string()), true);

Run

## Implementations

### impl dyn Any

[src]

#### pub fn is<T: Any>(&self) -> bool

[src]

Returns `true` if the boxed type is the same as `T`.

# Examples

    use std::any::Any;

    fn is_string(s: &dyn Any) {
        if s.is::<String>() {
            println!("It's a string!");
        } else {
            println!("Not a string...");
        }
    }

    is_string(&0);
    is_string(&"cookie monster".to_string());

Run

#### pub fn downcast_ref<T: Any>(&self) -> Option<&T>

[src]

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: &dyn Any) {
        if let Some(string) = s.downcast_ref::<String>() {
            println!("It's a string({}): '{}'", string.len(), string);
        } else {
            println!("Not a string...");
        }
    }

    print_if_string(&0);
    print_if_string(&"cookie monster".to_string());

Run

#### pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T>

[src]

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 dyn Any) {
        if let Some(num) = s.downcast_mut::<u32>() {
            *num = 42;
        }
    }

    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");

Run

### impl dyn Any + Send

[src]

#### pub fn is<T: Any>(&self) -> bool

[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn is_string(s: &(dyn Any + Send)) {
        if s.is::<String>() {
            println!("It's a string!");
        } else {
            println!("Not a string...");
        }
    }

    is_string(&0);
    is_string(&"cookie monster".to_string());

Run

#### pub fn downcast_ref<T: Any>(&self) -> Option<&T>

[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn print_if_string(s: &(dyn Any + Send)) {
        if let Some(string) = s.downcast_ref::<String>() {
            println!("It's a string({}): '{}'", string.len(), string);
        } else {
            println!("Not a string...");
        }
    }

    print_if_string(&0);
    print_if_string(&"cookie monster".to_string());

Run

#### pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T>

[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn modify_if_u32(s: &mut (dyn Any + Send)) {
        if let Some(num) = s.downcast_mut::<u32>() {
            *num = 42;
        }
    }

    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");

Run

### impl dyn Any + Send + Sync

[src]

#### pub fn is<T: Any>(&self) -> bool

1.28.0[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn is_string(s: &(dyn Any + Send + Sync)) {
        if s.is::<String>() {
            println!("It's a string!");
        } else {
            println!("Not a string...");
        }
    }

    is_string(&0);
    is_string(&"cookie monster".to_string());

Run

#### pub fn downcast_ref<T: Any>(&self) -> Option<&T>

1.28.0[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn print_if_string(s: &(dyn Any + Send + Sync)) {
        if let Some(string) = s.downcast_ref::<String>() {
            println!("It's a string({}): '{}'", string.len(), string);
        } else {
            println!("Not a string...");
        }
    }

    print_if_string(&0);
    print_if_string(&"cookie monster".to_string());

Run

#### pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T>

1.28.0[src]

Forwards to the method defined on the type `Any`.

# Examples

    use std::any::Any;

    fn modify_if_u32(s: &mut (dyn Any + Send + Sync)) {
        if let Some(num) = s.downcast_mut::<u32>() {
            *num = 42;
        }
    }

    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");

Run

## Trait Implementations

### impl Debug for dyn Any

[src]

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

[src]

Formats the value using the given formatter. Read more

### impl Debug for dyn Any + Send

[src]

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

[src]

Formats the value using the given formatter. Read more

### impl Debug for dyn Any + Send + Sync

1.28.0[src]

#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

[src]

Formats the value using the given formatter. Read more

## Implementors

### impl<T: 'static + ?Sized> Any for T

[src]

#### fn type_id(&self) -> TypeId

[src]