Timestamp and UUID support missing from Zero ∅ about scalaz HOT 4 CLOSED

Scalaz6 overloads the meaning of Zero a bit: it's both the Zero of the corresponding Monoid (ie, x + 0 = x), and this gets (ab--)used as a default value. Neither of these types forms a Monoid, so it's hard to add a reasonable Zero. It's likely that in Scalaz7 we will separate these better.

For now, I think it's more appropriate to add these to your own project. Just declare the implicits and import them; or declare them in your top level package object to avoid needing an import.

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Thanks @retronym, your suggestion sounds very sensible. I've tried adding the following to the package def:

// For ∅[java.util.UUID]
implicit def UUIDZero: Zero[UUID] = zero(null)

But I'm getting could not find implicit value for parameter z: scalaz.Zero[java.util.UUID] errors when I call it - any ideas what I'm doing wrong?

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Did you import it at the place you need it?

Try this at the place you want to use it:

(UUIDZero: Zero[UUID])

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Thanks @retronym, I didn't import it at the place of use because it's in the package definition. However it doesn't work either if I put the implicit def right next to the calling code :

implicit def UUIDZero: Zero[UUID] = zero(null)
def this() = this(∅[Long], ∅[UUID]) // Still throws error

I didn't understand where I should add the snippet in your last message? (UUIDZero: Zero[UUID] - any ideas much appreciated!

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