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.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

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