HHVM and Hack Documentation

Hack

Getting Started
Some simple steps to install Hack, writing and running your first program, and some information about Hack-related tools.
Source Code Fundamentals
The basic source-code elements, program structure, name scope, scripts and script inclusion, and namespaces.
Types
Predefined and user-defined types, type conversion, type aliasing, supertypes and subtypes, and type inferencing.
Expressions And Operators
Full expressions, side-effects, precedence and associativity, order-of-evaluation, and all the operators.
Statements
Compound statements, labeled statements, expression statements, selection statements, iteration statements, jump statements, and other statements.
Functions
Defining and calling functions and methods, and anonymous functions (writing closures and lambdas).
Classes
Defining basic classes, member visiblity, implementing interfaces, inheritance, and using traits.
Generic Types And Functions
Generic types and functions, type parameters, type constraints, type arguments, and variance.
Asynchronous Operations
How async programming lets apps scale better and reduces blocking.
Attributes
Declarative information that can be attached to various program entities, and retrieved at run-time via reflection.
XHP
A reusable and customizable UI system that automatically handles escaping and XSS protection.

Full reference docs for all functions, classes, interfaces, and traits in the Hack language.

Full reference docs for all functions, classes, interfaces, and traits in the Hack Standard Library (HSL).