Type Declarations

Calibre uses type declarations to introduce new named types.

type Pair := struct { left right : int };

This binds the name Pair to a struct type. The same type form is also used for enums, tuple-style structs, and generic types.

type Language := enum {
  ENGLISH : int,
  SPANISH,
  ARABIC : <Language, Language>
};

type Country := struct (Language);
type Box:<T> := struct { value : T };

Calibre also allows built-in types to be named in type declarations when overloading or extending them.

type int := int @overload {
  "+" := fn (left right : int) => left - right
};

Most of the time, though, type is simply how you define your own data shapes.

Once a type has been declared, it can be constructed, destructured, matched against, and extended just like the built-in types used throughout the rest of the tour.