Function Types

Functions are first-class and curried by default.

Example

add = (a: Number, b: Number): Number => a + b

Semantically this behaves like:

Number -> Number -> Number

Rules

• multi-parameter functions are curried automatically
• partial application is valid when argument types line up
• extra arguments are a type error
• functions are values, but not structurally comparable with ===

Why this matters

Function types show up everywhere in the standard library because pipes and partial application are central to the language style.