Type System

FScript uses static type inference.

Inference first

You often write no type annotations:

let add x y = x + y

The compiler infers int -> int -> int.

Optional annotations

Use annotations for clarity or constraints:

let scale (x: float) (y: float) : float = x * y

Function types

Curried function types are right-associative:

• int -> int -> int
• equivalent to int -> (int -> int)

Common type forms

• int, float, bool, string, unit
• 'a list
• 'a option
• tuples like (int * string)
• record and union types

Next

Read Structural vs Named Annotations for record annotation styles and guidance.