Hi,

In message "[ruby-talk:16025] Logical values in Ruby?"
    on 01/05/30, Juha Pohjalainen <voidjump / nic.fi> writes:

|Has anyone done Logical values (that is true, false or unknown) in
|Ruby? I see there is TrueClass (and only one instance of it; true)
|and FalseClass (and only one instance of it; false), but I don't
|see see UnknownClass (or only one instance of it; unknown).
|
|Any ideas? Or implementations already?

How about using `nil' for that purpose?

							matz.