Derive Macro

The Inject derive macro supports the two following attributes:

• #[provides]: Customizing the object registration.
• #[inject]: Customizing how an injected member is created.

#[derive(Inject)]
#[provides(PROPERTY...)]
struct Transient {
    #[inject(PROPERTY...)]
    field: UserType,
}

provides Properties

• transient [= "<TYPE-SIGNATURE>"]
  • The object is provided as a transient registered with <TYPE-SIGNATURE> as key. If the signature is omitted, the concrete type is used as a key.
• singleton [= "<TYPE-SIGNATURE>"]
  • The object is provided as a singleton registered with <TYPE-SIGNATURE> as key. If the signature is omitted, the concrete type is used as a key.
• ctor = <IDENTIFIER>
  • The object isn't constructed using member-wise construction, but it's constructed using a custom constructor (e.g., new). The constructor will be passed the members in order of declaration as parameters.
• no_registration
  • The type isn't registered automatically and the generated Self::register(&ferrunix::Registry) function needs to be called manually to register the type.

inject Properties

• default
  • Construct the field using the Default implementation.
• ctor = "<RUST-CODE>"
  • Construct the field using the provided Rust code.
• transient [= true]
  • Construct the field as a transient by retrieving it from the Registry.
• singleton [= true]
  • Construct the field as a singleton by retrieving it from the Registry.

Full Example

#![allow(unused)]
extern crate ferrunix;
use ferrunix::Inject;

pub trait Logger {}

#[derive(Inject)]
#[provides(transient = "dyn Logger", no_registration)]
//                   ^^^^^^^^^^^^^^
// The explicit type can be omitted, if it matches the concrete type.
pub struct MyLogger {}

impl Logger for MyLogger {}

#[derive(Inject)]
#[provides(singleton, no_registration)]
pub struct MyConfig {
    #[inject(default)]
    // Use the `Default::default` impl for construction.
    counter: u32,

    #[inject(ctor = r#""log-prefix: ".to_owned()"#)]
    //              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    // The constructor must be valid Rust code. For strings, two sets of quotes
    // are required.
    prefix: String,

    #[inject(transient /* = true */)]
    //                 ^^^^^^^^^^^^
    // The long form with `= true` is optional.
    logger: Box<dyn Logger>,
}

fn main() {
    let registry = ferrunix::Registry::empty();
    MyLogger::register(&registry);
    MyConfig::register(&registry);
}