Mojo language reference

Welcome to the Mojo language reference. This documentation provides a concise reference for Mojo's syntax—identifiers, keywords, literals, expressions, operators, statements, function declarations, and more. It's organized by grammar construct and is designed for quick lookup when you need the exact rules, precedence, or form of a specific language element.

Identifiers & keywords

Naming rules, reserved words, escaped identifiers, and argument conventions

Literals

Integer, floating-point, string, t-string, boolean, None, and Self literals

Expressions

Tuples, collection displays, member access, calls, subscripts, ternary conditionals, and comprehensions

Operators

Operator precedence, associativity, and implementing operators for custom types

Simple statements

Imports, assignments, return, raise, break, continue, and compile-time declarations

Compound statements

If statements, loops, error handling with try/except, context managers, and compile-time control flow

Function declarations

Signatures, parameters, arguments, default values, constraints, effects, and special methods