Mojo

Hello, Mojo:

def main():
    print("Hello Mojo!")

Uses a new CLI (magic) as the usual project management utility.

Supports both declared (var) and implicitly-declared variables. Uses optional type annotations. Indentation scoped. Comments are #-prefixed single-line.

Functions declared either by def or by fn (which requires argument and return types, and raises if it can raise an error). By default immutable reference argument passing, but allowing for declarations on arguments to indicate by value (owned) or by reference (read is immutable reference, mut as mutable reference).

Structs use Python class syntax, but are entirely static--bound at compile-time--allowing no dynamic dispatch or runtime changes to the struct.

Metaprogramming:

Traits are "like a template of characteristics for a struct".
Parameterization; "a parameter is a compile-time variable that becomes a runtime constant, and it's declared in square brackets on a function or struct." NOTE: "Many other languages use "parameter" and "argument" interchangeably, so be aware that when we say things like "parameter" and "parametric function," we're talking about these compile-time parameters. Whereas, a function "argument" is a runtime value that's declared in parentheses." (This is a huge point-of-definition/glossary obstacle/concern/point-of-awareness.)

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LogRocket: Getting Started

Tags: language macos linux python

Last modified 18 May 2025

Mojo

Bridges the gap between research and production by combining Python syntax and ecosystem with CPU+GPU, systems programming and metaprogramming features.

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