Iterate enumerated class instances

问题

Is there a simple way to iterate over all enumerated instances of a class in Ceylon?

Just like values() for Java enums?

abstract class Suit() of hearts | diamonds | clubs | spades {
    shared formal String name; 
}
object spades extends Suit() { name => "Spades"; }
object clubs extends Suit() { name => "Clubs"; }
object diamonds extends Suit() { name => "Diamonds"; }
object hearts extends Suit() { name => "Hearts"; }

Lets say I'd like to pick a random suit or I'd like to print all suits by their names.

Edit:

Explicitly adding all suits to an iterable works but we have to list all possible values again.

{Suit+} suits = {spades, clubs, diamonds, hearts};

Can somebody come up with something better?

回答1:

This can be done now with ClassOrInterface.caseValues:

Suit[] suits = `Suit`.caseValues;

Regarding the returned sequence:

This sequence is ordered and skips any case type to only include case values.

回答2:

One way is to use the metamodel:

for (caseType in `class Suit`.caseTypes) {
    assert (is OpenClassOrInterfaceType caseType);
    print(caseType.declaration.name);
}

来源：https://stackoverflow.com/questions/19402031/iterate-enumerated-class-instances