Struct Context

pub struct Context<'a> { /* private fields */ }

Stores type information about an entry inside of a TraitMap.

Must be cast to a TypedContext using the .downcast() or .try_downcast() methods for adding or removing traits from the map.

Implementations

impl<'a> Context<'a>

pub fn downcast<T>(self) -> TypedContext<'a, T>

where T: 'static,

Downcast into the concrete TypedContext.

Panics

This method panics if the type parameter T does not match the concrete type.

Examples

impl TraitMapEntry for MyStruct {
  fn on_create<'a>(&mut self, context: Context<'a>) {
    context
     .downcast::<Self>()
     .add_trait::<dyn ExampleTrait>()
     .add_trait::<dyn ExampleTraitTwo>();
  }
}

pub fn try_downcast<T>(self) -> Result<TypedContext<'a, T>, Self>

where T: 'static,

Try to downcast into a concrete TypedContext.

Errors

Returns None if the type parameter T does not match the concrete type.

Examples

impl TraitMapEntry for MyStruct {
  fn on_create<'a>(&mut self, context: Context<'a>) {
    if let Some(context) = context.try_downcast::<Self>() {
      context
       .add_trait::<dyn ExampleTrait>()
       .add_trait::<dyn ExampleTraitTwo>();
    }
  }
}

Trait Implementations

impl<'a> Debug for Context<'a>

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

Formats the value using the given formatter.