There's more power than that in spec. For example, you can globally define :address/zip to be a string that's more than, say, N characters long. Now anytime you

There's more power than that in spec. For example, you can globally define :address/zip to be a string that's more than, say, N characters long. Now anytime you encounter an :address/zip, regardless of whether it is inside, say :billing-address or :shipping-address dictionary/map, it can be checked for those function predicates.