add property labels for NewNode products (mostly for pretty printing) (#108)

Author: mpollmeier

codegen/src/main/scala/overflowdb/codegen/CodeGen.scala

@@ -1681,10 +1681,15 @@ class CodeGen(schema: Schema) {
 
       val classNameNewNode = s"New$nodeClassName"
 
-      val productElementAccessors = fieldDescriptions.reverse.zipWithIndex.map  {
+      val productElements = fieldDescriptions.reverse.zipWithIndex
+      val productElementAccessors = productElements.map {
         case (fieldDescription, index) =>
           s"case $index => this.${fieldDescription.name}"
       }.mkString("\n")
+      val productElementNames = productElements.map {
+        case (fieldDescription, index) =>
+          s"""case $index => "${fieldDescription.name}""""
+      }.mkString("\n")
 
       s"""object $classNameNewNode {
          |  def apply(): $classNameNewNode = new $classNameNewNode
@@ -1711,6 +1716,12 @@ class CodeGen(schema: Schema) {
          |      case _ => null
          |    }
          |
+         |  override def productElementName(n: Int): String =
+         |    n match {
+         |      $productElementNames
+         |      case _ => ""
+         |    }
+         |
          |  override def productPrefix = "$classNameNewNode"
          |  override def productArity = ${fieldDescriptions.size}
          |

integration-tests/tests/src/test/scala/Schema02Test.scala

@@ -21,6 +21,17 @@ class Schema02Test extends AnyWordSpec with Matchers {
   }
 
   "NewNode" can {
+    "be used as a product, e.g. for pretty printing" in {
+      val newNode = NewNode1().name("A").order(1)
+
+      newNode.productPrefix shouldBe "NewNode1"
+      newNode.productArity shouldBe 2
+      newNode.productElementName(0) shouldBe "order"
+      newNode.productElement(0) shouldBe Some(1)
+      newNode.productElementName(1) shouldBe "name"
+      newNode.productElement(1) shouldBe "A"
+    }
+
     "get copied and mutated" in {
       val original = NewNode1().name("A").order(1)