Migration to Scala 3

.gitignore

@@ -8,13 +8,19 @@
 # sbt specific
 .cache
 .history
-.lib/
-dist/*
-target/
-lib_managed/
-src_managed/
-project/boot/
-project/plugins/project/
-
+.lib
+dist
+target
+lib_managed
+src_managed
+project
+.scala-build
 
+# Tooling
+.project
+.metals
+.bsp
+.bloop
 
+# Testing
+test.png

.scalafmt.conf

@@ -0,0 +1,8 @@
+version = "3.7.15"
+runner.dialect = scala3
+
+assumeStandardLibraryStripMargin = true
+align.stripMargin = true
+
+binPack.unsafeCallSite = true
+binPack.literalArgumentLists = true

Vagrantfile

@@ -15,22 +15,21 @@ Vagrant.configure(2) do |config|
 
   config.vm.provision "shell", inline: <<-SHELL
 
-    # Refresh sources
+    # Refresh system
     sudo apt-get update -y
+    sudo apt-get upgrade -y
 
     # Graphviz for printing parsers to graphs
     sudo apt-get install -y graphviz
 
-    # Java
-    sudo apt-get install -y openjdk-7-jdk
-
     # Sbt
-    sudo mkdir -p /home/vagrant/bin
-    pushd /home/vagrant/bin/
-    sudo wget https://repo.typesafe.com/typesafe/ivy-releases/org.scala-sbt/sbt-launch/0.13.8/sbt-launch.jar
-    sudo cp /home/vagrant/configs/sbt.sh /home/vagrant/bin/sbt
-    sudo chmod u+x /home/vagrant/bin/sbt
-    sudo chmod +x /home/vagrant/bin/sbt
+    sudo apt-get install -y apt-transport-https curl gnupg
+    echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" | sudo tee /etc/apt/sources.list.d/sbt.list
+    echo "deb https://repo.scala-sbt.org/scalasbt/debian /" | sudo tee /etc/apt/sources.list.d/sbt_old.list
+    curl -sL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x2EE0EA64E40A89B84B2DF73499E82A75642AC823" | sudo -H gpg --no-default-keyring --keyring gnupg-ring:/etc/apt/trusted.gpg.d/scalasbt-release.gpg --import
+    sudo chmod 644 /etc/apt/trusted.gpg.d/scalasbt-release.gpg
+    sudo apt-get update -y
+    sudo apt-get install -y sbt
     popd
   SHELL
 

artifact/build.sbt

@@ -2,20 +2,19 @@ name := "first-class-derivatives"
 
 version := "1.0"
 
-scalaVersion := "2.11.7"
+scalaVersion := "3.7.3"
 
 scalacOptions ++= Seq("-feature", "-deprecation")
 
-libraryDependencies += "org.scalatest" %% "scalatest" % "2.2.4" % "test"
+libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.19" % "test"
 
-resolvers += "Sonatype OSS Snapshots" at
-  "https://oss.sonatype.org/content/repositories/releases"
+resolvers += "Sonatype OSS Snapshots" at "https://oss.sonatype.org/content/repositories/releases"
 
-parallelExecution in Test := true
+Test / parallelExecution := true
 
-libraryDependencies += "org.scala-lang.modules" % "scala-xml_2.11" % "1.0.5"
+libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "2.4.0"
 
-initialCommands in console := """import fcd._; import fcd.DerivativeParsers._"""
+console / initialCommands := """import fcd._; import fcd.DerivativeParsers._"""
 
 // For VM users on windows systems, please uncomment the following line:
 // target := file("/home/vagrant/target/")

artifact/src/main/scala/examples/PythonAst.scala

@@ -9,25 +9,24 @@ trait PythonAst {
   case class Decorated(decorators: Seq[Decorator], el: Any) extends Tree
 
   trait Def extends Tree
-  case class FuncDef(name: Any, params: Any, retAnnot: Option[Any], body: Any) extends Def
-
-  trait Stmt extends Tree
-  case class Simple(small: Seq[Any]) extends Stmt
-
-  case class Del(exprs: Seq[Any]) extends Stmt
-  case object Pass extends Stmt
-  case object Break extends Stmt
-  case object Continue extends Stmt
-  case class Return(expr: Option[Any]) extends Stmt
-  case class Raise(expr: Option[Any]) extends Stmt
-  case class ExprStmt(expr: Any) extends Stmt
-  case class Import(names: Any, from: Option[Any] = None) extends Stmt
-
-  case class Global(ids: Seq[Any]) extends Stmt
-  case class Nonlocal(ids: Seq[Any]) extends Stmt
-  case class Assert(tests: Seq[Any]) extends Stmt
-
-  case class For(exprs: Seq[Any], in: Any, body: Any, default: Any) extends Stmt
+  case class FuncDef(name: Any, params: Any, retAnnot: Option[Any], body: Any)
+      extends Def
+
+  enum Stmt extends Tree {
+    case Simple(small: Seq[Any])
+    case Del(exprs: Seq[Any])
+    case Pass
+    case Break
+    case Continue
+    case Return(expr: Option[Any])
+    case Raise(expr: Option[Any])
+    case ExprStmt(expr: Any)
+    case Import(names: Any, from: Option[Any] = None)
+    case Global(ids: Seq[Any])
+    case Nonlocal(ids: Seq[Any])
+    case Assert(tests: Seq[Any])
+    case For(exprs: Seq[Any], in: Any, body: Any, default: Any)
+  }
 
   trait Expr extends Tree
   case class BinOp(l: Any, op: Any, r: Any) extends Expr