parser: use ast user data to store attribution

buildext/src/main/kotlin/gay/pizza/pork/buildext/ast/AstCodegen.kt

@@ -18,6 +18,7 @@ class AstCodegen(val pkg: String, val outputDirectory: Path, val world: AstWorld
     for (type in world.typeRegistry.types) {
       writeAstType(type)
     }
+    writeNodeExtensions()
     writeNodeType()
     writeNodeVisitors()
     writeNodeCoalescer()
@@ -124,7 +125,6 @@ class AstCodegen(val pkg: String, val outputDirectory: Path, val world: AstWorld
     visitAllFunction.body.add(
       "nodeLists.asSequence().flatten().filterNotNull().map { visit(it) }.toList()")
     visitorExtensionSet.functions.add(visitAllFunction)
-
     write("NodeVisitorExtensions.kt", KotlinWriter(visitorExtensionSet))
   }
 
@@ -190,12 +190,22 @@ class AstCodegen(val pkg: String, val outputDirectory: Path, val world: AstWorld
     }
 
     if (role == AstTypeRole.RootNode) {
+      kotlinClassLike.imports.add("kotlinx.serialization.Transient")
       val typeMember = KotlinMember(
         "type",
         "NodeType",
         abstract = true
       )
       kotlinClassLike.members.add(typeMember)
+      val dataMember = KotlinMember(
+        "data",
+        "Any?",
+        value = "null",
+        mutable = true,
+        notInsideConstructor = true,
+        annotations = mutableListOf("@Transient")
+      )
+      kotlinClassLike.members.add(dataMember)
 
       val abstractVisitChildrenFunction = KotlinFunction(
         "visitChildren",
@@ -389,6 +399,21 @@ class AstCodegen(val pkg: String, val outputDirectory: Path, val world: AstWorld
     write("${type.name}.kt", KotlinWriter(kotlinClassLike))
   }
 
+  private fun writeNodeExtensions() {
+    val nodeExtensionSet = KotlinFunctionSet(pkg)
+    val dataFunction = KotlinFunction(
+      "data",
+      typeParameters = mutableListOf("P"),
+      extensionOf = "Node",
+      returnType = "P?",
+      isImmediateExpression = true,
+      annotations = mutableListOf("""@Suppress("UNCHECKED_CAST")""")
+    )
+    dataFunction.body.add("data as? P?")
+    nodeExtensionSet.functions.add(dataFunction)
+    write("NodeExtensions.kt", KotlinWriter(nodeExtensionSet))
+  }
+
   private fun toKotlinType(typeRef: AstTypeRef): String {
     val baseType = typeRef.type?.name ?: typeRef.primitive?.id
       ?: throw RuntimeException("Unable to determine base type.")

buildext/src/main/kotlin/gay/pizza/pork/buildext/codegen/KotlinMember.kt

@@ -6,5 +6,9 @@ class KotlinMember(
   var abstract: Boolean = false,
   var overridden: Boolean = false,
   var value: String? = null,
-  var mutable: Boolean = false
+  var mutable: Boolean = false,
+  var private: Boolean = false,
+  var protected: Boolean = false,
+  var notInsideConstructor: Boolean = false,
+  var annotations: MutableList<String> = mutableListOf()
 )

buildext/src/main/kotlin/gay/pizza/pork/buildext/codegen/KotlinWriter.kt

@@ -15,7 +15,7 @@ class KotlinWriter() {
     }
     writeClassLike(classType, kotlinClass)
     val members = kotlinClass.members.filter {
-      it.abstract || (it.overridden && it.value != null)
+      it.abstract || (it.overridden && it.value != null) || it.notInsideConstructor
     }
     if (members.isEmpty() && kotlinClass.functions.isEmpty()) {
       appendLine()
@@ -23,13 +23,23 @@ class KotlinWriter() {
       appendLine(" {")
     }
 
-    for (member in members) {
-      val form = if (member.mutable) "var" else "val"
+    for ((index, member) in members.withIndex()) {
+      for (annotation in member.annotations) {
+        appendLine("  $annotation")
+      }
+
+      val privacy = when {
+        member.private -> "private "
+        member.protected -> "protected "
+        else -> ""
+      }
+      val form = if (member.mutable) "${privacy}var" else "${privacy}val"
       if (member.abstract) {
         appendLine("  abstract $form ${member.name}: ${member.type}")
       } else {
+        append("  ")
         if (member.overridden) {
-          append("  override ")
+          append("override ")
         }
         append("$form ${member.name}: ${member.type}")
         if (member.value != null) {
@@ -38,6 +48,10 @@ class KotlinWriter() {
         }
         appendLine()
       }
+
+      if (index != members.size - 1) {
+        appendLine()
+      }
     }
 
     if (members.isNotEmpty() && kotlinClass.functions.isNotEmpty()) {
@@ -109,7 +123,7 @@ class KotlinWriter() {
     }
 
     val contructedMembers = kotlinClass.members.filter {
-      !it.abstract && !(it.overridden && it.value != null)
+      !it.abstract && !(it.overridden && it.value != null) && !it.notInsideConstructor
     }
 
     if (contructedMembers.isNotEmpty()) {