Injection

Injection exists because the injected objects are globally immutable. They can only be temporarily overridden within the current scope. When calling a function, even if it has its own environment, it still has access to the injected objects. This is somewhat similar to the define feature in Racket. However, since Felys introduces variables, it is not allowed to inject objects during runtime; instead, this should be done at the Rust level.

Initialization

We use Rust's built-in HashMap<String, Object> type to store all the objects. The String represents the identifier, and Object is the corresponding Felys object. It is recommended to use HashMap::from() to generate this hash map.

let mixin = HashMap::from([
    ("one".to_string(), Object::Number(1.0))，
    ("two".to_string(), Object::Number(2.0)),
]);

Inject

Inject it when building the Worker:

Worker::new(mixin, 0.0, 100, Language::EN);

Then, when you use the Worker to execute code, this code will have access to these two constants. See more details on the next page.