Migrate to Scala 3

build.sbt

@@ -1,10 +1,10 @@
 ThisBuild / organization := "io.latis-data"
-ThisBuild / scalaVersion := "2.13.12"
+ThisBuild / scalaVersion := "3.3.1"
 
 val fs2DataVersion = "1.8.1"
 val http4sVersion = "0.23.25"
-val latisVersion = "ea2ab6c"
-val latisHapiVersion = "e30933f"
+val latisVersion  = "4abcef6" //TODO: update when latis3's scala-3 branch is merged
+val latisHapiVersion = "3e21c35" //TODO: update when latis3-hapi's scala-3 branch is merged
 
 lazy val root = (project in file("."))
   .settings(

src/main/scala/latis/ops/ConvertHapiTypes.scala

@@ -1,10 +1,10 @@
 package latis.ops
 
-import cats.syntax.all._
+import cats.syntax.all.*
 
-import latis.data._
-import latis.data.Data._
-import latis.model._
+import latis.data.*
+import latis.data.Data.*
+import latis.model.*
 import latis.util.LatisException
 
 /**

src/main/scala/latis/ops/ToHapiTime.scala

@@ -1,9 +1,9 @@
 package latis.ops
 
-import cats.implicits._
+import cats.implicits.*
 
 import latis.data.Sample
-import latis.model._
+import latis.model.*
 import latis.time.Time
 import latis.time.TimeFormat
 import latis.util.LatisException

src/main/scala/latis/service/hapi/AboutResponse.scala

@@ -28,7 +28,7 @@ final case class AboutResponse(
 object AboutResponse {
 
   /** JSON encoder */
-  implicit val encoder: Encoder[AboutResponse] =
+  given encoder: Encoder[AboutResponse] =
     Encoder.forProduct8(
       "version",
       "status",
@@ -48,4 +48,4 @@ object AboutResponse {
       ar.contactId,
       ar.citation
     ) }.mapJson(_.dropNullValues)
-}
+}

src/main/scala/latis/service/hapi/AboutService.scala

@@ -1,9 +1,9 @@
 package latis.service.hapi
 
 import cats.effect.Concurrent
-import io.circe.syntax._
+import io.circe.syntax.*
 import org.http4s.HttpRoutes
-import org.http4s.circe._
+import org.http4s.circe.*
 import org.http4s.dsl.Http4sDsl
 
 import latis.util.LatisConfig

src/main/scala/latis/service/hapi/Bin.scala

@@ -1,7 +1,7 @@
 package latis.service.hapi
 
 import io.circe.Encoder
-import io.circe.generic.semiauto._
+import io.circe.generic.semiauto.*
 
 /**
  * Represents a parameter's bin.
@@ -25,16 +25,16 @@ final case class Bin(
 object Bin {
 
   /** JSON encoder */
-  implicit val encoder: Encoder[Bin] =
+  given encoder: Encoder[Bin] =
     deriveEncoder[Bin].mapJsonObject { obj =>
       obj.filter {
         case ("centers", _) =>
           // Keep "centers" regardless of its value if "ranges" is
           // null or missing.
-          obj("ranges").map(_.isNull).getOrElse(true)
+          obj("ranges").forall(_.isNull)
         case (_, v)         =>
           // Remove all other null fields.
           !v.isNull
       }
     }
-}
+}

src/main/scala/latis/service/hapi/Capabilities.scala

@@ -18,7 +18,7 @@ final case class Capabilities(
 object Capabilities {
 
   /** JSON encoder */
-  implicit val encoder: Encoder[Capabilities] =
+  given encoder: Encoder[Capabilities] =
     Encoder.forProduct3("HAPI", "status", "outputFormats") { x =>
       (x.version, x.status, x.formats)
     }

src/main/scala/latis/service/hapi/CapabilitiesService.scala

@@ -1,9 +1,9 @@
 package latis.service.hapi
 
 import cats.effect.Concurrent
-import io.circe.syntax._
+import io.circe.syntax.*
 import org.http4s.HttpRoutes
-import org.http4s.circe._
+import org.http4s.circe.*
 import org.http4s.dsl.Http4sDsl
 
 /** Implements the `/capabilities` endpoint. */

src/main/scala/latis/service/hapi/Catalog.scala

@@ -18,7 +18,7 @@ final case class Catalog(
 object Catalog {
 
   /** JSON encoder */
-  implicit val encoder: Encoder[Catalog] =
+  given encoder: Encoder[Catalog] =
     Encoder.forProduct3("HAPI", "status", "catalog") { x =>
       (x.version, x.status, x.catalog)
     }

src/main/scala/latis/service/hapi/CatalogService.scala

@@ -1,10 +1,10 @@
 package latis.service.hapi
 
 import cats.effect.Concurrent
-import cats.implicits._
-import io.circe.syntax._
+import cats.implicits.*
+import io.circe.syntax.*
 import org.http4s.HttpRoutes
-import org.http4s.circe._
+import org.http4s.circe.*
 import org.http4s.dsl.Http4sDsl
 
 /**

src/main/scala/latis/service/hapi/DataService.scala

@@ -3,22 +3,22 @@ package latis.service.hapi
 import cats.data.EitherT
 import cats.data.NonEmptyList
 import cats.effect.Concurrent
-import cats.implicits._
+import cats.implicits.*
 import fs2.Stream
-import io.circe.syntax._
+import io.circe.syntax.*
 import org.http4s.{Status => _, _}
-import org.http4s.circe._
+import org.http4s.circe.*
 import org.http4s.dsl.Http4sDsl
 import org.http4s.headers.`Content-Type`
-import org.log4s._
+import org.log4s.*
 
 /** Implements the `/data` endpoint. */
 class DataService[F[_]: Concurrent](
   alg: DataAlgebra[F] with InfoAlgebra[F]
 ) extends Http4sDsl[F] {
-  import Format._
-  import Include._
-  import QueryDecoders._
+  import Format.*
+  import Include.*
+  import QueryDecoders.*
 
   private[this] val logger = getLogger
 

src/main/scala/latis/service/hapi/DataType.scala

@@ -7,25 +7,25 @@ import io.circe.Json
 sealed trait DataType
 
 /** String data */
-final case object HString extends DataType
+case object HString extends DataType
 
 /** Double data, 8-byte IEEE 754 format */
-final case object HDouble extends DataType
+case object HDouble extends DataType
 
 /** Integer data, 4-byte signed, little-endian */
-final case object HInteger extends DataType
+case object HInteger extends DataType
 
 /** Time string data, restricted ISO 8601 */
-final case object HIsoTime extends DataType
+case object HIsoTime extends DataType
 
 object DataType {
-
+  
   /** JSON encoder */
-  implicit val encoder: Encoder[DataType] =
+  given encoder: Encoder[DataType] =
     Encoder.instance {
       case HString  => Json.fromString("string")
       case HDouble  => Json.fromString("double")
       case HInteger => Json.fromString("integer")
       case HIsoTime => Json.fromString("isotime")
     }
-}
+}

src/main/scala/latis/service/hapi/Dataset.scala

@@ -29,7 +29,7 @@ object Dataset {
     Dataset(id, id)
 
   /** JSON encoder */
-  implicit val encoder: Encoder[Dataset] =
+  given encoder: Encoder[Dataset] =
     Encoder.forProduct2("id", "title") { x =>
       (x.id, x.title)
     }

src/main/scala/latis/service/hapi/Format.scala

@@ -1,20 +1,20 @@
 package latis.service.hapi
 
-import cats.implicits._
+import cats.implicits.*
 import org.http4s.ParseFailure
 import org.http4s.QueryParamDecoder
 import org.http4s.QueryParameterValue
-import org.http4s.dsl.io._
+import org.http4s.dsl.io.*
 
 /** Wrapper for `format` parameter. */
 sealed trait Format
 
 object Format {
-  final case object Csv extends Format
-  final case object Binary extends Format
-  final case object Json extends Format
+  case object Csv extends Format
+  case object Binary extends Format
+  case object Json extends Format
 
-  implicit val formatDecoder: QueryParamDecoder[Format] =
+  given formatDecoder: QueryParamDecoder[Format] =
     new QueryParamDecoder[Format] {
       override def decode(qpv: QueryParameterValue) = qpv.value match {
         case "csv" => Csv.validNel

src/main/scala/latis/service/hapi/HapiError.scala

@@ -16,7 +16,7 @@ object HapiError {
     HapiError(HapiService.version, status)
 
   /** JSON encoder */
-  implicit val encoder: Encoder[HapiError] =
+  given encoder: Encoder[HapiError] =
     Encoder.forProduct2("HAPI", "status") { x =>
       (x.version, x.status)
     }

src/main/scala/latis/service/hapi/HapiInterpreter.scala

@@ -3,7 +3,7 @@ package latis.service.hapi
 import cats.Applicative
 import cats.data.EitherT
 import cats.data.NonEmptyList
-import cats.implicits._
+import cats.implicits.*
 import fs2.Stream
 import io.circe.JsonObject
 

src/main/scala/latis/service/hapi/HapiService.scala

@@ -1,7 +1,7 @@
 package latis.service.hapi
 
 import cats.effect.IO
-import cats.implicits._
+import cats.implicits.*
 import org.http4s.HttpRoutes
 
 import latis.catalog.Catalog

src/main/scala/latis/service/hapi/Include.scala

@@ -1,17 +1,17 @@
 package latis.service.hapi
 
-import cats.implicits._
+import cats.implicits.*
 import org.http4s.ParseFailure
 import org.http4s.QueryParamDecoder
 import org.http4s.QueryParameterValue
-import org.http4s.dsl.io._
+import org.http4s.dsl.io.*
 
 /** Wrapper for `include` parameter. */
 final case class Include(header: Boolean) extends AnyVal
 
 object Include {
 
-  implicit val includeDecoder: QueryParamDecoder[Include] =
+  given includeDecoder: QueryParamDecoder[Include] =
     new QueryParamDecoder[Include] {
       override def decode(qpv: QueryParameterValue) = qpv.value match {
         case "header" => Include(true).validNel

src/main/scala/latis/service/hapi/InfoResponse.scala

@@ -2,7 +2,7 @@ package latis.service.hapi
 
 import io.circe.Encoder
 import io.circe.Json
-import io.circe.syntax._
+import io.circe.syntax.*
 
 /**
  * Represents a response from the `info` service.
@@ -24,7 +24,7 @@ object InfoResponse {
    *
    * Note that we are flattening out the `metadata` field.
    */
-  implicit val encoder: Encoder[InfoResponse] =
+  given encoder: Encoder[InfoResponse] =
     new Encoder[InfoResponse] {
       override def apply(x: InfoResponse): Json =
         Encoder[Metadata].apply(x.metadata).deepMerge(

src/main/scala/latis/service/hapi/InfoService.scala

@@ -2,16 +2,16 @@ package latis.service.hapi
 
 import cats.data.EitherT
 import cats.effect.Concurrent
-import cats.implicits._
-import io.circe.syntax._
+import cats.implicits.*
+import io.circe.syntax.*
 import org.http4s.HttpRoutes
-import org.http4s.circe._
+import org.http4s.circe.*
 import org.http4s.dsl.Http4sDsl
-import org.log4s._
+import org.log4s.*
 
 /** Implements the `/info` endpoint. */
 class InfoService[F[_]: Concurrent](alg: InfoAlgebra[F]) extends Http4sDsl[F] {
-  import QueryDecoders._
+  import QueryDecoders.*
 
   private[this] val logger = getLogger
 

src/main/scala/latis/service/hapi/LandingPageService.scala

@@ -1,12 +1,12 @@
 package latis.service.hapi
 
 import cats.Monad
-import cats.syntax.all._
+import cats.syntax.all.*
 import org.http4s.HttpRoutes
 import org.http4s.dsl.Http4sDsl
-import org.http4s.scalatags._
+import org.http4s.scalatags.*
 import scalatags.Text
-import scalatags.Text.all._
+import scalatags.Text.all.*
 
 /** Implements the HAPI landing page. */
 class LandingPageService[F[_]: Monad](alg: CatalogAlgebra[F]) extends Http4sDsl[F] {

src/main/scala/latis/service/hapi/Latis3Interpreter.scala

@@ -5,7 +5,7 @@ import scala.collection.immutable.ListMap
 import cats.data.EitherT
 import cats.data.NonEmptyList
 import cats.effect.IO
-import cats.implicits._
+import cats.implicits.*
 import fs2.Stream
 import fs2.data.json
 import fs2.data.json.circe.tokenizerForEncoder
@@ -31,10 +31,10 @@ import latis.output.BinaryEncoder
 import latis.output.CsvEncoder
 import latis.output.JsonEncoder
 import latis.time.{Time => LTime}
-import latis.util.HapiUtils._
+import latis.util.HapiUtils.*
 import latis.util.Identifier
-import latis.util.Identifier.IdentifierStringContext
-import latis.util.dap2.parser.ast._
+import latis.util.Identifier.*
+import latis.util.dap2.parser.ast.*
 import latis.util.hapi.DataCodec
 
 class Latis3Interpreter(catalog: Catalog) extends HapiInterpreter[IO] {
@@ -67,7 +67,7 @@ class Latis3Interpreter(catalog: Catalog) extends HapiInterpreter[IO] {
       // This would indicate that the parameter wasn't found, so we
       // should return an error.
       missing   = params.flatMap(_.find(! hasVariable(dataset, _)))
-      _        <- EitherT.fromOption[IO](missing.map(UnknownParam), ()).swap
+      _        <- EitherT.fromOption[IO](missing.map(UnknownParam.apply), ()).swap
       // Get the metadata.
       metadata <- EitherT.fromEither[IO](getDatasetMetadata(dataset))
     } yield params.map { ps =>

src/main/scala/latis/service/hapi/Metadata.scala

@@ -2,7 +2,7 @@ package latis.service.hapi
 
 import cats.data.NonEmptyList
 import io.circe.Encoder
-import io.circe.generic.semiauto._
+import io.circe.generic.semiauto.*
 
 /**
  * Represents metadata for HAPI datasets.
@@ -44,7 +44,7 @@ object Metadata {
    *
    * This encoder will drop parameters that are None.
    */
-  implicit val encoder: Encoder[Metadata] =
+  given encoder: Encoder[Metadata] =
     deriveEncoder[Metadata].mapJsonObject {
       _.filter {
         case (_, v) => !v.isNull