Version: 1.1.0

Creating values

A value begins in an initializer. Mojo generates the simple ones and lets you write the rest.

Essentials

__init__(out self) is the constructor. out means self starts uninitialized.
@fieldwise_init generates an initializer with one argument per field.
A copy initializer builds a value from an existing one.
Factory functions are ordinary functions that return the struct.
Every field must be initialized before the constructor returns.

@fieldwise_init
struct Color:
    var r: Int
    var g: Int
    var b: Int

def main():
    var ink = Color(20, 20, 20)
    print(ink.r)

Do not use a field before it has been stored. The compiler treats that read as uninitialized.