Types: Introduction

Hack includes a strong static type system. This section covers the basic features of the type checker.

See also the is operator for checking the type of a value, and the as operator for asserting types.

Topics covered in this section

• Subtyping
• Soft Types
• Nullable Types
• Type Aliases (newtype and type)
• Type Conversion
• Type Inferencing
• Type Refinement
• lambda
• Generic Types