Bump code-snippets to Scala 3.0.0/Clean-up (#78)

- Bump to Scala 3.0.0
- Bump to sbt 1.5.2 and clean-up build
- Adapt sample code to align with final Scala 3 syntax
- Duplicate some worksheets to Scala source files to demonstrate
  aspects of generated code

Author: eloots

code-snippets/build.sbt

@@ -1,17 +1,13 @@
-val dottyVersion = "0.27.0-RC1"
 
 Global / onChangedBuildSource := ReloadOnSourceChanges
 
 lazy val `dotty-snippets` = project
   .in(file("."))
-  .settings(ThisBuild / scalaVersion := dottyVersion)
+  .settings(ThisBuild / scalaVersion := "3.0.0-RC3")
   .settings(
     name := "dotty-simple",
     version := "0.1.0",
 
-    //ThisBuild / scalaVersion := dottyVersion,
-    ThisBuild / scalaVersion := dottyLatestNightlyBuild.get,
-
     libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % "test"
   )
   .aggregate(

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/CollectiveExtensions.scala

@@ -0,0 +1,17 @@
+// Metals Scala worksheet
+
+extension (i: Int)
+  def isEven: Boolean = i % 2 == 0
+
+  def unary_! : Int = -i
+
+  def square : Int = i * i
+
+extension [T](xs: List[T])
+  def second: T = xs.tail.head
+  def third: T = xs.tail.second
+
+println(List(1,2,3).second)
+println(! 5)
+println(5.isEven)
+println(5.square)

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/CollectiveExtensions.worksheet.sc

@@ -0,0 +1,8 @@
+// Metals Scala worksheet
+
+extension (a: String) def < (b: String): Boolean = a.compareTo(b) < 0
+  
+extension (a: Int) def  +++: (b: List[Int]) = a::b
+
+println("abc" < "pqr")
+println(1 +++: List(2,3,4))

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/ExtensionOperators.scala

@@ -1,4 +1,6 @@
-package org.lunatech.dotty.extensionmethods
+// Metals Scala worksheet
+
+import scala.annotation.targetName
 
 extension [T](xs: List[T])
   def second =
@@ -9,13 +11,17 @@ extension [T](xs: List[List[T]])
     xs.foldLeft[List[T]](Nil)(_ ++ _)
 
 extension [T: Numeric](x: T)
-  def  + (y: T): T =
+  def +++ (y: T): T =
     summon[Numeric[T]].plus(x, y)
+  def --- (y: T): T = 
+    summon[Numeric[T]].minus(x, y)
 
-def [T: Numeric](x: T) - (y: T) = summon[Numeric[T]].plus(x, y)
+1 --- 2
+2 +++ 1
 
 case class Circle(x: Double, y: Double, radius: Double)
-def (c: Circle).circumference: Double = c.radius * math.Pi * 2
 
-@main def circles() =
-  println(s"Circle: ${Circle(1.0, 2.0, 4).circumference}")
+extension (c: Circle) 
+  def circumference: Double = c.radius * math.Pi * 2
+
+Circle(1.0, 2.0, 4).circumference

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/ExtensionOperators.worksheet.sc

@@ -0,0 +1,9 @@
+// Metals Scala worksheet
+extension (i: Int)
+  def isEven: Boolean = i % 2 == 0
+
+  def unary_! : Int = -i
+
+println(3.isEven)
+println(!5)
+

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/GenericExtension.scala renamed to code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/GenericExtension.worksheet.sc

@@ -1,10 +1,11 @@
 trait IntOps:
-  extension (i: Int) def isZero: Boolean = i == 0
+  extension (i: Int) 
+    def isZero: Boolean = i == 0
 
-  extension (i: Int) def safeMod(x: Int): Option[Int] =
-    // extension method defined in same scope IntOps
-    if x.isZero then None
-    else Some(i % x)
+    def safeMod(x: Int): Option[Int] =
+      // extension method defined in same scope IntOps
+      if x.isZero then None
+      else Some(i % x)
 
 object IntOpsEx extends IntOps:
   extension (i: Int) def safeDiv(x: Int): Option[Int] =
@@ -20,30 +21,19 @@ object SafeDiv:
     (i.safeDiv(d), i.safeMod(d)) match
       case (Some(d), Some(r)) => Some((d, r))
       case _ => None
-  
-  val d1 = 25.divide(3)
-  val d2 = 25.divide(0)
 
-SafeDiv.d1
-SafeDiv.d2
+import SafeDiv._
+val n = 9
+val d1 = 25.divide(3)
+val d2 = 25.divide(0)
 
-given IntOps
+given IntOps = new IntOps{}
 
 20.safeMod(0)
 20.safeMod(3)
 
 extension [T](xs: List[List[T]])
   def flatten: List[T] = xs.foldLeft(Nil: List[T])(_ ++ _)
 
-given [T: Ordering] as Ordering[List[T]]:
-  override def compare(l1: List[T], l2: List[T]): Int = 1
-  extension (xs: List[T])
-    def < (ys: List[T]): Boolean = summon[Ordering[T]].lt(xs.head, ys.head)
-
-
 // extension method available since it is in the implicit scope of List[List[Int]]
 List(List(1, 2), List(3, 4)).flatten
-
-// extension method available since it is in the given Ordering[List[T]],
-// which is itself in the implicit scope of List[Int]
-List(1, 2) < List(3)

code-snippets/contextual-abstractions/src/main/scala/org/lunatech/dotty/extensionmethods/IntOps.scala

@@ -1,19 +1,17 @@
-package org.lunatech.dotty.givens
 
 sealed trait Engine
 final case class CarEngine(cylinder: Int) extends Engine
 final case class TruckEngine(cylinder: Int) extends Engine
 
-trait Starter[T] {
+trait Starter[T]:
   def start(e: T): Unit
-}
 
-given Starter[CarEngine] {
+given Starter[CarEngine] with {
   override def start(engine: CarEngine): Unit = 
     println(s"Starting CarEngine with ${engine.cylinder} cylinder(s)")
 }
 
-given Starter[TruckEngine] {
+given Starter[TruckEngine] with {
   override def start(engine: TruckEngine): Unit = 
     println(s"Starting TruckEngine with ${engine.cylinder} cylinder(s)")
 }
@@ -23,9 +21,6 @@ def startEngine[E <: Engine: Starter](engine: E): Unit = {
   starter.start(engine)
 }
 
-@main def testSummon(): Unit = {
-
-  startEngine(CarEngine(6))
-  startEngine(TruckEngine(8))
-  startEngine(TruckEngine(1))(using summon[Starter[TruckEngine]])
-}
+startEngine(CarEngine(6))
+startEngine(TruckEngine(8))
+startEngine(TruckEngine(1))(using summon[Starter[TruckEngine]])