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knightpop/TaggedTypeAnswer.sc

Created September 9, 2017 17:54
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TaggedTypeAnswer.sc
import shapeless.tag
import shapeless.tag.@@
trait UserIdTag
trait DeviceUuidTag
trait CarSerialIdTag
type UserId = Long @@ UserIdTag
type DeviceUuid = Long @@ DeviceUuidTag
type CarSerialId = Long @@ CarSerialIdTag
def getHashCodeTagged(userId: UserId, deviceUuid: DeviceUuid, carSerialId: CarSerialId): String = {
val userIdPlus: Long = userId + 1
val deviceUuidPlus: Long = deviceUuid + 2
val carSerialIdPlus: Long = carSerialId + 3
s"$userIdPlus-$deviceUuidPlus-$carSerialIdPlus"
}
val taggedUserId: UserId = tag[UserIdTag][Long](userId)
val taggedDeviceUuid: DeviceUuid = tag[DeviceUuidTag][Long](deviceUuid)
val taggedCarSerialId: CarSerialId = tag[CarSerialIdTag][Long](carSerialId)
getHashCodeTagged(taggedUserId, taggedDeviceUuid, taggedCarSerialId) // Right Answer = res2: String = 13-1236-12348
getHashCodeTagged(taggedDeviceUuid, taggedCarSerialId, taggedUserId) // Not Even Compiled
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