Rm cats from engine

build.sbt

@@ -1,6 +1,3 @@
-import java.io.FileInputStream
-import java.util.Properties
-
 ThisBuild / name := "inkuire"
 ThisBuild / organization := "org.virtuslab"
 
@@ -28,7 +25,7 @@ ThisBuild / developers := List(
 )
 
 publish / skip := true
-ThisBuild / scalaVersion := "2.13.4"
+ThisBuild / scalaVersion := "2.13.8"
 
 
 ThisBuild / scalafixDependencies += "com.github.liancheng" %% "organize-imports" % "0.5.0"
@@ -37,11 +34,12 @@ ThisBuild / semanticdbVersion := scalafixSemanticdb.revision
 ThisBuild / scalafixScalaBinaryVersion := CrossVersion.binaryScalaVersion(scalaVersion.value)
 ThisBuild / scalacOptions ++= Seq(
   "-Yrangepos",
-  "-Ywarn-unused"
+  "-Ywarn-unused",
+  "-deprecation",
+  "-feature"
 )
 
 val http4sVersion = "0.21.0"
-val catsVersion = "2.2.0"
 val circeVersion = "0.13.0"
 
 lazy val inkuireEngine = crossProject(JSPlatform, JVMPlatform)
@@ -51,8 +49,6 @@ lazy val inkuireEngine = crossProject(JSPlatform, JVMPlatform)
     libraryDependencies ++= Seq(
       "com.softwaremill.quicklens" %%% "quicklens" % "1.7.2",
       "org.scala-lang.modules" %%% "scala-parser-combinators" % "1.1.2",
-      "org.typelevel" %%% "cats-core" % catsVersion,
-      "org.typelevel" %%% "cats-effect" % catsVersion,
       "io.circe" %%% "circe-core" % circeVersion,
       "io.circe" %%% "circe-parser" % circeVersion,
       "io.circe" %%% "circe-generic" % circeVersion,

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/api/ConfigReader.scala

@@ -1,9 +1,10 @@
 package org.virtuslab.inkuire.engine.common.api
 
-import cats.data.EitherT
-import cats.effect.IO
+import org.virtuslab.inkuire.engine.common.api.FutureExcept
 import org.virtuslab.inkuire.engine.common.model.AppConfig
 
+import scala.concurrent.ExecutionContext
+
 trait ConfigReader {
-  def readConfig(args: Seq[String]): EitherT[IO, String, AppConfig]
+  def readConfig(args: Seq[String])(implicit ec: ExecutionContext): FutureExcept[AppConfig]
 }

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/api/FutureExcept.scala

@@ -0,0 +1,34 @@
+package org.virtuslab.inkuire.engine.common.api
+
+import scala.concurrent.ExecutionContext
+import scala.concurrent.Future
+
+case class FutureExcept[A](value: Future[Either[String, A]]) {
+  def map[B](f: A => B)(implicit ec: ExecutionContext): FutureExcept[B] =
+    new FutureExcept(value.map(_.map(f)))
+
+  def flatMap[B](f: A => FutureExcept[B])(implicit ec: ExecutionContext): FutureExcept[B] =
+    new FutureExcept(
+      value.flatMap {
+        case Left(value)  => Future(Left(value))
+        case Right(value) => f(value).value
+      }
+    )
+
+  def semiflatmap[B](f: A => Either[String, B])(implicit ec: ExecutionContext): FutureExcept[B] =
+    new FutureExcept(value.map(_.flatMap(f)))
+
+  def mapInner[B](f: Either[String, A] => Either[String, B])(implicit ec: ExecutionContext): FutureExcept[B] =
+    new FutureExcept(value.map(f))
+}
+
+object FutureExcept {
+  def pure[A](a: A)(implicit ec: ExecutionContext): FutureExcept[A] =
+    FutureExcept(Future(Right(a)))
+
+  def fromExcept[A](e: Either[String, A])(implicit ec: ExecutionContext): FutureExcept[A] =
+    FutureExcept(Future(e))
+
+  def fromFuture[A](f: Future[A])(implicit ec: ExecutionContext): FutureExcept[A] =
+    FutureExcept(f.map(Right.apply[String, A]))
+}

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/api/InkuireRunner.scala

@@ -1,39 +1,48 @@
 package org.virtuslab.inkuire.engine.common.api
 
-import cats.effect.IO
 import org.virtuslab.inkuire.engine.common.model._
 import org.virtuslab.inkuire.engine.common.parser.ScalaSignatureParserService
 import org.virtuslab.inkuire.engine.common.service.DefaultSignatureResolver
 import org.virtuslab.inkuire.engine.common.service.ScalaExternalSignaturePrettifier
 import org.virtuslab.inkuire.engine.common.service.SubstitutionMatchService
 import org.virtuslab.inkuire.engine.common.service.TopLevelMatchQualityService
 
+import scala.concurrent.ExecutionContext
+import scala.concurrent.Future
+import scala.util.chaining._
+
 class InkuireRunner(
-  configReader:        ConfigReader,
-  inputHandler:        InputHandler,
-  outputHandler:       OutputHandler,
-  parser:              BaseSignatureParserService,
-  resolver:            InkuireDb => BaseSignatureResolver,
-  matchService:        InkuireDb => BaseMatchService,
-  matchQualityService: InkuireDb => BaseMatchQualityService,
-  prettifier:          BaseSignaturePrettifier
+  val configReader:        ConfigReader,
+  val inputHandler:        InputHandler,
+  val outputHandler:       OutputHandler,
+  val parser:              BaseSignatureParserService,
+  val resolver:            InkuireDb => BaseSignatureResolver,
+  val matchService:        InkuireDb => BaseMatchService,
+  val matchQualityService: InkuireDb => BaseMatchQualityService,
+  val prettifier:          BaseSignaturePrettifier
 ) {
 
-  def run(args: Seq[String]): IO[Unit] =
+  def run(args: Seq[String])(implicit ec: ExecutionContext): Future[Unit] =
     configReader
       .readConfig(args)
       .flatMap { config: AppConfig =>
         inputHandler
           .readInput(config)
-          .semiflatMap { db: InkuireDb =>
+          .flatMap { db: InkuireDb =>
             outputHandler
-              .serveOutput()
-              .runA(
-                Engine.Env(db, matchService(db), matchQualityService(db), prettifier, parser, resolver(db), config)
+              .serveOutput(
+                Env(db, matchService(db), matchQualityService(db), prettifier, parser, resolver(db), config)
               )
+              .pipe(FutureExcept.fromFuture)
           }
       }
-      .fold(str => println(s"Oooooh man, bad luck. Inkuire encountered an unexpected error. Caused by $str"), identity)
+      .value
+      .map(
+        _.fold(
+          str => println(s"Oooooh man, bad luck. Inkuire encountered an unexpected error. Caused by $str"),
+          identity
+        )
+      )
 
 }
 

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/api/InputHandler.scala

@@ -1,10 +1,11 @@
 package org.virtuslab.inkuire.engine.common.api
 
-import cats.data.EitherT
-import cats.effect.IO
+import org.virtuslab.inkuire.engine.common.api.FutureExcept
 import org.virtuslab.inkuire.engine.common.model.AppConfig
 import org.virtuslab.inkuire.engine.common.model.InkuireDb
 
+import scala.concurrent.ExecutionContext
+
 trait InputHandler {
-  def readInput(appConfig: AppConfig): EitherT[IO, String, InkuireDb]
+  def readInput(appConfig: AppConfig)(implicit ec: ExecutionContext): FutureExcept[InkuireDb]
 }

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/api/OutputHandler.scala

@@ -1,18 +1,12 @@
 package org.virtuslab.inkuire.engine.common.api
 
-import cats.data.StateT
-import cats.effect.IO
-import cats.implicits._
-import org.virtuslab.inkuire.engine.common.model.Engine.Env
-import org.virtuslab.inkuire.engine.common.model.Engine._
+import org.virtuslab.inkuire.engine.common.model.Env
+
+import scala.concurrent.ExecutionContext
+import scala.concurrent.Future
 
 trait OutputHandler {
-  def serveOutput(env: Env): IO[Unit] =
-    serveOutput().runA(env)
 
-  def serveOutput(): Engine[Unit] = {
-    StateT.get[IO, Env] >>= { env =>
-      this.serveOutput(env).liftApp
-    }
-  }
+  def serveOutput(env: Env)(implicit ec: ExecutionContext): Future[Unit]
+
 }

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/model/AppConfig.scala

@@ -1,24 +1,26 @@
 package org.virtuslab.inkuire.engine.common.model
 
-import cats.kernel.Monoid
+import org.virtuslab.inkuire.engine.common.utils.Monoid
 
 case class AppConfig(
-  address:      Option[String],
-  port:         Option[Int],
-  inkuirePaths: Seq[String]
+  address:      Option[String] = None,
+  port:         Option[Int] = None,
+  inkuirePaths: Seq[String] = Seq.empty
 ) {
   def getAddress: String = address.getOrElse("0.0.0.0")
   def getPort:    Int    = port.getOrElse(8080)
 }
 
 object AppConfig {
+  def empty: AppConfig = AppConfig(
+    address = None,
+    port = None,
+    inkuirePaths = Seq.empty
+  )
+
   implicit val appConfigMonoid: Monoid[AppConfig] = new Monoid[AppConfig] {
-    def empty: AppConfig = AppConfig(
-      address = None,
-      port = None,
-      inkuirePaths = Seq.empty
-    )
-    def combine(x: AppConfig, y: AppConfig): AppConfig =
+    def empty: AppConfig = AppConfig.empty
+    def mappend(x: AppConfig, y: AppConfig): AppConfig =
       AppConfig(
         address = x.address.orElse(y.address),
         port = x.port.orElse(y.port),
@@ -28,11 +30,11 @@ object AppConfig {
 
   def parseCliOption(opt: String, v: String): AppConfig =
     opt match {
-      case "-a" | "--address" => Monoid.empty[AppConfig].copy(address = Some(v))
-      case "-p" | "--port"    => Monoid.empty[AppConfig].copy(port = Some(v.toInt))
-      case "-i" | "--inkuire" => Monoid.empty[AppConfig].copy(inkuirePaths = Seq(v))
+      case "-a" | "--address" => AppConfig(address = Some(v))
+      case "-p" | "--port"    => AppConfig(port = Some(v.toInt))
+      case "-i" | "--inkuire" => AppConfig(inkuirePaths = Seq(v))
       case o =>
         println(s"Inkuire ignored wrong option: $o")
-        Monoid.empty[AppConfig]
+        AppConfig.empty
     }
 }

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/model/Env.scala

@@ -0,0 +1,13 @@
+package org.virtuslab.inkuire.engine.common.model
+
+import org.virtuslab.inkuire.engine.common.api._
+
+case class Env(
+  db:                  InkuireDb,
+  matcher:             BaseMatchService,
+  matchQualityService: BaseMatchQualityService,
+  prettifier:          BaseSignaturePrettifier,
+  parser:              BaseSignatureParserService,
+  resolver:            BaseSignatureResolver,
+  appConfig:           AppConfig
+)

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/model/InkuireDb.scala

@@ -1,8 +1,8 @@
 package org.virtuslab.inkuire.engine.common.model
 
-import cats.kernel.Monoid
+import org.virtuslab.inkuire.engine.common.utils.Monoid
 
-//TODO technically it would be better to have a different type for type declarations -> types: Map[ITID, (Declaration, Seq[Type])]
+// TODO(kπ) technically it would be better to have a different type for type declarations -> types: Map[ITID, (Declaration, Seq[Type])]
 case class InkuireDb(
   functions:           Seq[ExternalSignature],
   types:               Map[ITID, (Type, Seq[Type])],
@@ -12,7 +12,7 @@ case class InkuireDb(
 
 object InkuireDb {
   implicit val inkuireDbMonoid: Monoid[InkuireDb] = new Monoid[InkuireDb] {
-    override def combine(x: InkuireDb, y: InkuireDb): InkuireDb =
+    override def mappend(x: InkuireDb, y: InkuireDb): InkuireDb =
       InkuireDb(
         functions = (x.functions ++ y.functions).distinct,
         types = (x.types.toSeq ++ y.types.toSeq).distinct

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/model/SignatureContext.scala

@@ -1,6 +1,6 @@
 package org.virtuslab.inkuire.engine.common.model
 
-import cats.kernel.Monoid
+import org.virtuslab.inkuire.engine.common.utils.Monoid
 
 case class SignatureContext(
   vars:        Set[String],
@@ -20,7 +20,7 @@ object SignatureContext {
   implicit val signatureContextMonoid: Monoid[SignatureContext] = new Monoid[SignatureContext] {
     override def empty: SignatureContext = SignatureContext(Set.empty, Map.empty)
 
-    override def combine(x: SignatureContext, y: SignatureContext): SignatureContext = {
+    override def mappend(x: SignatureContext, y: SignatureContext): SignatureContext = {
       SignatureContext(
         x.vars ++ y.vars,
         x.constraints ++ y.constraints

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/model/TypeName.scala

@@ -1,5 +1,7 @@
 package org.virtuslab.inkuire.engine.common.model
 
+import scala.language.implicitConversions
+
 case class TypeName(name: String) {
   override def hashCode(): Int = name.toLowerCase.hashCode
 

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/parser/BaseSignatureParser.scala

@@ -1,6 +1,5 @@
 package org.virtuslab.inkuire.engine.common.parser
 
-import cats.Monoid
 import org.virtuslab.inkuire.engine.common.model.Type
 import org.virtuslab.inkuire.engine.common.model._
 
@@ -16,7 +15,7 @@ abstract class BaseSignatureParser extends RegexParsers {
     (typ <~ ",") ~ list(typ) ^^ { case head ~ tail => head +: tail } |
       typ ^^ (Seq(_))
 
-  def empty[T](implicit monoid: Monoid[T]): Parser[T] = "" ^^^ monoid.empty
+  def empty[A]: Parser[List[A]] = "" ^^^ List.empty
 
   def genericType: Parser[Type]
 

engine/shared/src/main/scala/org/virtuslab/inkuire/engine/common/parser/ScalaSignatureParser.scala

@@ -1,7 +1,5 @@
 package org.virtuslab.inkuire.engine.common.parser
 
-import cats.instances.all._
-import cats.syntax.all._
 import com.softwaremill.quicklens._
 import org.virtuslab.inkuire.engine.common.api._
 import org.virtuslab.inkuire.engine.common.model._
@@ -76,9 +74,9 @@ class ScalaSignatureParser extends BaseSignatureParser {
       case baseType ~ types => Type(baseType, types.map(UnresolvedVariance))
     }
 
-  def types: Parser[Seq[TypeLike]] = list(typeLike) | empty[List[TypeLike]]
+  def types: Parser[Seq[TypeLike]] = list(typeLike) | empty[TypeLike]
 
-  def typeArguments: Parser[Seq[TypeLike]] = list(typeLike) | empty[List[TypeLike]]
+  def typeArguments: Parser[Seq[TypeLike]] = list(typeLike) | empty[TypeLike]
 
   def typeVariable: Parser[(String, Seq[Type])] =
     (identifier <~ "<:") ~ singleType ^^ { case typeVar ~ constraint => (typeVar, Seq(constraint)) } |
@@ -144,7 +142,10 @@ class ScalaSignatureParserService extends BaseSignatureParserService {
   private val scalaSignatureParser = new ScalaSignatureParser
 
   override def parse(str: String): Either[String, ParsedSignature] =
-    doParse(str) map convert map (s => curry(s)) >>= validate
+    doParse(str)
+      .map(convert)
+      .map(curry)
+      .flatMap(validate)
 
   val parsingErrorGenericMessage =
     "Could not parse provided signature. Example signature looks like this: List[Int] => (Int => Boolean) => Int"