Types and contracts

pub data Box<T>(value: T) generate Display;

pub contract Greeter { fun greet(name: Text) -> Text; }

pub class DelegatedGreeting impl Greeter {
    private fix delegate: Greeter;
    init(delegate: Greeter) { self.delegate = delegate; }
    forward Greeter to delegate;
}

Public types live in a matching .kalm file; facade functions live in <FileName>Kalm. Java sees ordinary public methods, constructors, records and interfaces. override fun is required for interface implementations and inherited overrides. Forwarding preserves substituted Java generic signatures and checked exceptions.

Other type forms include base class with needs fun, closed class with nested permitted subclasses, choice enums, singleton, and generic alias. Classes and methods are final by default; use extendable where extension is intended.