Derive Macro Component 

#[derive(Component)]
{
    // Attributes available to this derive:
    #[component]
    #[autowired]
}

Derive macro for automatic component registration and dependency injection

The Component derive macro automatically implements the ComponentInitializer trait and registers the component with the IoC container. It handles dependency injection for fields marked with #[autowired] and provides sensible defaults for other fields.

Attributes

• #[autowired] - Marks a field for automatic dependency injection. The field must be of type Arc<T>
• #[component(scope = "...")] - Sets the component scope (defaults to Singleton)

Field Initialization Rules

1. Autowired fields: Automatically injected by the container
2. Option fields: Initialized to None
3. Other fields: Initialized using Default::default()

Examples

use verdure::Component;
use std::sync::Arc;

// Simple component with no dependencies
#[derive(Component)]
struct ConfigService {
    config_path: String, // Will be initialized with Default::default() = ""
    port: u16,           // Will be initialized with Default::default() = 0
}

// Component with dependencies
#[derive(Component)]
struct DatabaseService {
    #[autowired]
    config: Arc<ConfigService>, // Automatically injected
    optional_cache: Option<String>, // Initialized to None
    connection_pool_size: usize,    // Default::default() = 0
}

// Component with custom scope
#[derive(Component)]
#[component(scope = "Prototype")]
struct RequestHandler {
    #[autowired]
    db: Arc<DatabaseService>,
    request_id: String,
}

Generated Code

The macro generates implementations of ComponentInitializer and registers the component with the global registry using the inventory crate.

Panics

The macro will produce compile-time errors in the following cases:

• Applying to enums or unions (only structs with named fields are supported)
• Using #[autowired] on fields that are not Arc<T>
• Invalid syntax in component attributes