Enums

Enums are used to represent types that have multiple variants (sometimes called tagged unions or sum types). These are useful for datums and redeemers.

Example of an enum:

enum Redeemer {
	Cancel
	Buy { buyer: PubKeyHash }
}

// instantiating an enum:
const my_redeemer = Redeemer::Buy { PubKeyHash::new(#...) } 
// type of 'my_redeemer' is inferred

Note: the OOP analogy of an enum is an abstract class, and the enum variants can be thought of as concrete implementations (i.e. child classes).

Note: enum variants without fields don't use braces.

Methods

Like structs, methods can be places inside enum blocks.

The un-annotated self argument of enum methods, is implicitly typed as the enum base type.

Data

Data is a special builtin enum with 5 members:

• Date::IntData
• Data::ByteArrayData
• Data::ListData
• Data::MapData
• Data::ConstrData

A switch expression over Data can use any of these as case types:

data.switch{
	i: IntData => ...,
	b: ByteArrayData => ...,
	l: ListData => ...,
	m: MapData => ...,
	c: ConstrData => ... 
}

Note: the default _ case can also be used as a substitute for any of these cases.