From 8da1bd8492bb606713dc22635458b13859290e28 Mon Sep 17 00:00:00 2001
From: Aditya Naik
Date: Thu, 17 Feb 2022 00:01:37 -0800
Subject: initial

---
 .gitignore       |  5 +++
 .scalafmt.conf   | 11 +++++++
 build.sbt        |  5 +++
 playground.scala | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 .scalafmt.conf
 create mode 100644 build.sbt
 create mode 100644 playground.scala

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0044308
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+.bloop
+.bsp
+.metals
+project
+target
\ No newline at end of file
diff --git a/.scalafmt.conf b/.scalafmt.conf
new file mode 100644
index 0000000..2faf33f
--- /dev/null
+++ b/.scalafmt.conf
@@ -0,0 +1,11 @@
+version=3.0.0-RC7
+rules = [
+
+  # DisableSyntax
+  # ExplicitResultTypes
+  #LeakingImplicitClassVal
+  RemoveUnused
+  #NoAutoTupling 
+  #NoValInForComprehension 
+  #ProcedureSyntax
+]
\ No newline at end of file
diff --git a/build.sbt b/build.sbt
new file mode 100644
index 0000000..2b2b9ef
--- /dev/null
+++ b/build.sbt
@@ -0,0 +1,5 @@
+scalaVersion := "2.13.5"
+
+libraryDependencies ++= Seq(
+  "com.chuusai" %% "shapeless" % "2.3.3"
+)
diff --git a/playground.scala b/playground.scala
new file mode 100644
index 0000000..290c54c
--- /dev/null
+++ b/playground.scala
@@ -0,0 +1,92 @@
+
+import shapeless.Generic
+
+class Playground {
+  class ScalaStdlibTypes {
+    class ScalaConcreteTypesWithTypes {
+      type Rect = (Int, Int)
+      type Circle = Int
+      type Shape = Either[Rect, Circle]
+
+      def area(s: Shape) = s match {
+        case Left((a, b)) => a*b
+        case Right(a) => math.Pi*a*a
+      }
+
+      val rect: Shape = Left(4, 2)
+      val circle: Shape = Right(1)
+      println(area(rect), area(circle))
+    }
+    val concrete_types = new ScalaConcreteTypesWithTypes
+
+    class ScalaGenericTypes {
+      trait Shape
+      case class Rect(a: Int, b: Int) extends Shape
+      case class Circle(a: Int) extends Shape
+
+      def area(s: Shape) = s match {
+        case Rect(a, b) => a*b
+        case Circle(a) => math.Pi*a*a
+      }
+
+      val rect = new Rect(3, 4)
+      val circle = new Circle(3)
+      println(area(rect))
+    }
+    val generic_types = new ScalaGenericTypes
+  }
+
+  class ShapelessGenericTypes {
+    class FromTuples {
+      import shapeless.{HList, ::, HNil}
+      type testType = Int :: Int :: HNil
+      val k: testType = (1 :: 1 :: HNil) // manual construction of a "repr" (generic representation of a type) from a tuple
+
+      val newType = Generic[(Int, Int)]
+      println(newType.to((1, 1)))
+    }
+    class FromCaseClasses {
+      trait Shape
+      case class Rect(a: Int, b: Int) extends Shape
+
+      val rectGen = Generic[Rect]      
+      println(rectGen)
+    }
+    val case_classes = new FromCaseClasses
+  }
+
+  // val stdlib_types = new ScalaStdlibTypes
+  val shapless_generic_types = new ShapelessGenericTypes
+
+  class GenericCSVEncoder {
+    trait CSVEncoder[A] { // generic typeclass that defines the encode operation
+      def encode(s: A): List[String]
+    }
+    def writeCSV[A](vals: List[A])(implicit enc: CSVEncoder[A]): String =
+      vals.map(v => enc.encode(v).mkString(",")).mkString("\n")
+
+    /** Simple example with a case class
+      */
+    case class Employee(a: String, b: Int)
+    implicit val employeeEncoder: CSVEncoder[Employee] = {
+      new CSVEncoder[Employee] {
+        def encode(e: Employee): List[String] = List(e.a, e.b.toString)
+      }
+    }
+    val employees = List(Employee("a", 1), Employee("b", 2))
+    println(writeCSV(employees))
+  }
+  val generic_csv_encoder = new GenericCSVEncoder
+
+  class ShapelessCSVEncoder {
+    trait CSVEncoder[A] {
+      def encode(s: A): List[String]
+    }
+  }
+}
+
+object main {
+  def main(args: Array[String]): Unit = {
+    new Playground()
+  }
+}
-- 
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