Trait ObjectOps

Source

pub trait ObjectOps {
    // Required methods
    fn is<T: 'static>(&self) -> bool;
    fn to<T: 'static>(self) -> Result<T, Object>;
    fn to_ref<T: 'static>(&self) -> Option<&T>;
}

Expand description

Conversion and downcasting helpers for owned reflective objects.

Implemented for Object, ObjectMut and SendObject. Owned conversion consumes the wrapper and returns the reflected value as an Object when the requested concrete type does not match, while borrowed conversion leaves the wrapper in place.

Required Methods§

Source

fn is<T: 'static>(&self) -> bool

Checks whether the object stores a T.

Source

fn to<T: 'static>(self) -> Result<T, Object>

Converts the boxed object into T, returning the reflected value as an Object when its concrete type does not match.

To try several target types, use Result::or_else to call to again on the returned Object, as shown in the example.

§Example

use typex::{Meta, ObjectOps, SendObject};

#[derive(Debug, Meta)]
#[typex(opaque)]
struct Count(u8);

#[derive(Debug, Meta)]
#[typex(opaque)]
struct Label(&'static str);

let describe = |object: SendObject| {
  object
    .to::<Count>()
    .map(|count| count.0.to_string())
    .or_else(|remaining| {
      remaining
        .to::<Label>()
        .map(|label| label.0.to_string())
    })
    .unwrap()
};

assert_eq!(describe(SendObject::new(Count(23))), "23");
assert_eq!(describe(SendObject::new(Label("hello"))), "hello");