Enums

Learn about creating enums, which allow you to create variables that are constrained to a specific set of values.

In Yarn Spinner, enums let you create variables whose value is constrained to a pre-defined list of possibilities.

An enum (short for ‘enumeration’) is useful when you have a variable that needs to have a wider range of possible values than simply true or false, but needs to be more specific than a number or string.

To define an enum you must provide a name, and some cases for it. Here's a new enum called Food with the cases Apple, Orange, and Pear:

<<enum Food>>
  <<case Apple>>
  <<case Orange>>
  <<case Pear>>
<<endenum>>

Once you've created an enum, you can use it just like any other variable:

// Declare a new variable with the default value Food.Apple
<<declare $favouriteFood = Food.Apple>>

// You can set $favouriteFood to the 'apple', 'orange' or 'pear'
// cases, but nothing else!
<<set $favouriteFood to Food.Orange>>

// You can use enums in if statements, like any other type of value:
<<if $favouriteFood == Food.Apple>>
  I love apples!
<<endif>>

// You can even skip the name of the enum if Yarn Spinner can 
// figure it out from context!
<<set $favouriteFood = .Pear>>