Trait Requires 

pub trait Requires<Capability: ?Sized>: Environment {
    // Required method
    fn Require(&self) -> Arc<Capability>;
}

A trait that enables an environment (Self) to provide a specific capability (Capability).

This is the central mechanism for dependency injection. An ActionEffect can be generic over an environment TEnvironment as long as it has the bound TEnvironment: Requires<MyCapability>. The effect can then call Environment.Require() to receive a shared instance of the service it needs to perform its operation.

The Capability is typically a trait object, such as dyn FileSystemReader.

Required Methods

fn Require(&self) -> Arc<Capability>

Returns the required capability from the environment, wrapped in an Arc for safe, shared ownership.

Implementations on Foreign Types

impl<TEnvironment: Requires<Capability> + ?Sized, Capability: ?Sized> Requires<Capability> for Arc<TEnvironment>

A blanket implementation that allows an Arc<TEnvironment> to provide a capability if the inner environment TEnvironment can provide it.

This is a crucial piece of ergonomics that allows code to call .Require() directly on a shared Arc<TEnvironment> reference without needing to dereference it first, simplifying effect implementation logic.

fn Require(&self) -> Arc<Capability>

Fulfills the requirement by dereferencing the Arc and calling the Require method on the inner environment TEnvironment.

Implementors