26.04.13 11:00, Greg Ewing написав(ла):
However, there's a worse problem with defining enum
inheritance that way. The subtype relation for extensible
enums works the opposite way to that of classes.
To see this, imagine a function expecting something
of type Colors. It knows what to do with red, green and
blue, but not anything else. So you *can't* pass it
something of type MoreColors, because not all values
of type MoreColors are of type Colors.
This is why enums are not subclassable in other languages (i.e. Java).
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