@fieldwise_init

You can add the @fieldwise_init decorator on a struct to generate the field-wise __init__() constructor.

For example, consider a simple struct like this:

@fieldwise_init
struct MyPet:
    var name: String
    var age: Int

Mojo sees the @fieldwise_init decorator and synthesizes a field-wise constructor, the result being as if you had actually written this:

struct MyPet:
    var name: String
    var age: Int

    fn __init__(out self, var name: String, age: Int):
        self.name = name^
        self.age = age

You can also synthesize the copy constructor and move constructor by adding the Copyable and Movable traits to your struct. For more information about these lifecycle methods, read Life of a value.