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Generics & Interfaces

RGC supports generic functions, generic classes, and generic enums, with interfaces providing static dispatch and bounds.

Generic functions​

def first[T](items: @List[T]) -> T {
    return items[0]
}

Generic classes​

class Pair[A, B] {
    first: A
    second: B
}

Generic enums​

enum Option[T] {
    Some(value: T)
    None
}

Interfaces​

Interfaces define behavioral contracts; types implement them:

interface Show {
    def to_string(self) -> str
}

class Point {
    x: int
    y: int
}

implement Show for Point {
    def to_string(self) -> str {
        return "({}, {})".format(self.x, self.y)
    }
}

Bounds​

Generic parameters can be constrained by interfaces:

def print_all[T: Show](items: @List[T]) {
    for item in items {
        print(item.to_string())
    }
}

Monomorphization​

Generics are compiled via monomorphization: each concrete type gets specialized code — no vtable overhead, no boxing, with performance identical to hand-written specialized implementations.

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