abstract Bool isMaybe()

Return if the choice slot allows zero selections

abstract Bool isMultiChoice()

Return if the choice slot allows multiple selections

abstract Spec? selection(Dict instance, Bool checked := true)

Return single choice selection considering validation rules. This method is a semantically equivalent to:

selections(instance, checked).first

abstract Spec[] selections(Dict instance, Bool checked := true)

Return all choice selections the given instance implements.

• one selection => return list of one
• zero selections + isMaybe is true => return empty list
• zero selections + isMaybe is false + checked is false => return empty list
• zero selections + isMaybe is false + checked is true => raise exception
• multiple selections + isMultiChoice is false + checked is false => return all
• multiple selections + isMultiChoice is false + checked is true => raise exception
• multiple selections + isMultiChoice is true + checked is true => return all

abstract Spec spec()

Spec for this choice - might be slot or choice type

abstract Spec type()

Choice type for the spec