In dynamic languages like Python, you can pass any object to any function. But you must make sure the object implements the methods you call in that function, or you’ll get a nasty runtime error.

This is where Traits come, like an abstract type, create a trait and declare a function but don’t implement it, in fact implementation and default values are not supported (yet).

Any function inheriting this trait should implement its methods.

trait Shape:
    fn area(self) -> Float64:
        ...

@value
struct Circle(Shape):
    var radius: Float64

    fn area(self) -> Float64:
        return 3.141592653589793 * self.radius ** 2


fn print_area[T: Shape](shape: T):
    print(shape.area())

• Traits can inherent from other traits.