Defaultable

Describes a type with a default constructor.

The Defaultable trait has a default implementation of __init__() that uses reflection to default-construct every field. This means simple structs can conform to Defaultable without implementing any methods:

@fieldwise_init
struct Point(Defaultable):
    var x: Int
    var y: Int

var p = Point()  # x == 0, y == 0

All fields must conform to Defaultable. Override __init__() for custom default semantics:

struct Foo(Defaultable):
    var s: String

    def __init__(out self):
        self.s = "default"

You can now construct a generic Defaultable type:

def default_init[T: Defaultable]() -> T:
    return T()

var foo = default_init[Foo]()
print(foo.s)

default

Implemented traits

AnyType

Provided methods

__init__

def __init__(out self)

Creates a default instance of the value.

The default implementation uses reflection to default-construct all fields in place. All fields must conform to Defaultable.

Returns:

_Self