OOPs concepts in Mojo

Warning

WIP: OOPs programming concepts is Not Available yet. This chapter is Work in Progress.

Structures

You can build high-level abstractions for types (or “objects”) in a struct.

A struct in Mojo is similar to a class in Python: they both support methods, fields, operator overloading, decorators for meta-programming, etc.

However, Mojo struct are completely static. Mojo struct are bound at compile-time, so they do not allow dynamic dispatch or any runtime changes to the structure. (Mojo will also support classes in the future.)

Here is one basic struct example.

struct MyPair:
    var first: Int
    var second: Int

    fn __init__(inout self, first: Int, second: Int):
        self.first = first
        self.second = second
    
    fn dump(self):
        print(self.first, self.second)

call struct

let mine = MyPair(2, 4)
mine.dump()

If you’re familiar with Python, then the init() method and the self argument should be familiar to you. If you’re not familiar with Python, then notice that, when we call dump(), we don’t actually pass a value for the self argument. The value for self is automatically provided with the current instance of the struct (it’s used similar to the this name used in some other languages to refer to the current instance of the object/type).

For much more detail about struct and other special methods like init() (also known as “dunder” methods), see the programming manual.