removed internal Map use, the keys aren't needed

parsley-debug/shared/src/main/scala/parsley/debug/DebugTree.scala

@@ -42,21 +42,17 @@ private [debug] abstract class DebugTree extends Iterable[DebugTree] {
 
     /** What are the child debug nodes for this node?
       *
-      * The map provided by the implementation should be a linked map in order to preserve the
-      * order of child parser occurrences within each parser.
-      *
-      * Internally, child nodes are given an arbitrary numeric suffix to disambiguate them in the map
-      * if multiple child nodes have the same parser name. This also allows one to traverse the tree
-      * down specific nodes via keys.
-      *
-      * Those internal names are not represented if checking [[parserName]].
+      * To preserve the order of child parser occurrences within each parser, this necessarily
+      * must be a sequence: List is convenient for processing.
       */
     def nodeChildren: List[DebugTree]
 
 // $COVERAGE-OFF$
     /** Provides a depth-first view of the tree as an iterator. */
-    override def iterator: Iterator[DebugTree] = Iterator(this) ++ nodeChildren.flatMap(_.iterator)
+    override def iterator: Iterator[DebugTree] = Iterator(this) ++ nodeChildren.iterator.flatMap(_.iterator)
 
+    // this isn't needed, but apparently the only place where the keys were referenced in the internal
+    // maps...
     /*override def toString: String = {
         val possibleChildNumber = childNumber.map(", " + _.toString).getOrElse("")
         val hasSuccess          = parseResults.exists(_.success)
@@ -65,10 +61,4 @@ private [debug] abstract class DebugTree extends Iterable[DebugTree] {
         s"DebugTree { name: $parserName ($internalName$possibleChildNumber), success: $hasSuccess, children: $keys }"
     }*/
 }
-
-/*private [debug] object DebugTree {
-    def unapply(dt: DebugTree): Some[(String, String, Option[Long], String, Option[ParseAttempt], Map[String, DebugTree])] = {
-        Some((dt.parserName, dt.internalName, dt.childNumber, dt.fullInput, dt.parseResults, dt.nodeChildren))
-    }
-}*/
 // $COVERAGE-ON$

parsley-debug/shared/src/main/scala/parsley/debug/internal/DebugContext.scala

@@ -43,7 +43,7 @@ private [parsley] class DebugContext(private val toStringRules: PartialFunction[
         XAssert.assert(!(ch.size > 1), s"The root tree has somehow gained multiple children. (${ch.size})")
 
         // This should never fail.
-        ch.valuesIterator.next()
+        ch.head
     }
 
     // Add an attempt of parsing at the current stack point.
@@ -69,20 +69,21 @@ private [parsley] class DebugContext(private val toStringRules: PartialFunction[
     }
 
     // Unique parser IDs.
-    private var uid = -1L
+    /*private var uid = -1L
     private def nextUid(): Long = {
         uid += 1L
         uid
-    }
+    }*/
 
     // Push a new parser onto the parser callstack.
     def push(fullInput: String, parser: LazyParsley[_], userAssignedName: Option[String]): Unit = {
         val newTree = new TransientDebugTree(fullInput = fullInput)
         newTree.name = Renamer.nameOf(userAssignedName, parser)
         newTree.internal = Renamer.internalName(parser)
 
-        val uid = nextUid()
-        builderStack.head.children(s"${newTree.name}-#$uid") = newTree
+        //val uid = nextUid()
+        //builderStack.head.children(s"${newTree.name}-#$uid") = newTree
+        builderStack.head.children += newTree
         builderStack.prepend(newTree)
     }
 

parsley-debug/shared/src/main/scala/parsley/debug/internal/TransientDebugTree.scala

@@ -5,11 +5,9 @@
  */
 package parsley.debug.internal
 
-import scala.collection.immutable.ListMap
 import scala.collection.mutable
 
 import parsley.debug.{DebugTree, ParseAttempt}
-import parsley.debug.util.XMap
 
 /** A mutable implementation of [[DebugTree]], used when constructing the tree as a parser is
   * running.
@@ -23,7 +21,7 @@ import parsley.debug.util.XMap
   */
 private [parsley] class TransientDebugTree(var name: String = "", var internal: String = "", val fullInput: String,
                                            var parse: Option[ParseAttempt] = None, var cNumber: Option[Long] = None,
-                                           val children: mutable.LinkedHashMap[String, TransientDebugTree] = mutable.LinkedHashMap.empty) extends DebugTree {
+                                           val children: mutable.ListBuffer[TransientDebugTree] = mutable.ListBuffer.empty) extends DebugTree {
     // These are user-facing, and will depend heavily on what the parser looks like.
     // $COVERAGE-OFF$
     override def parserName: String = name
@@ -35,20 +33,7 @@ private [parsley] class TransientDebugTree(var name: String = "", var internal:
     // The pair stores the input the parser attempted to parse and its success.
     override def parseResults: Option[ParseAttempt] = parse
 
-    // FIXME: doesn't this repeatedly remake the tree? when is this called?
-    // TODO: I'm pretty sure nothing ever uses this as a map! this could be a list
-    // which would be far more efficient (it also appears that nothing ever uses the keys?)
-    // TODO: move the name into the DebugTree or remove them entirely...
-    override def nodeChildren: List[DebugTree] = new XMap[String, DebugTree] {
-        // We'll use a copy-on-write methodology for these two -- remember, ordering is important!
-        override def removed(key: String): Map[String, DebugTree] = ListMap.empty ++ children - key
-        override def updated[V1 >: DebugTree](key: String, value: V1): Map[String, V1] = (ListMap.empty ++ children).updated(key, value)
-
-        // For get, size and iterator, we'll just use the mutable map.
-        override def get(key: String): Option[DebugTree] = children.get(key)
-        override def iterator: Iterator[(String, DebugTree)] = children.iterator
-        override def size: Int = children.size
-    }.values.toList
+    override def nodeChildren: List[DebugTree] = children.toList
 
     // Factors out inputs or results for parsers with children.
     private type Augment  = (Long, (Int, Int))
@@ -74,7 +59,7 @@ private [parsley] class TransientDebugTree(var name: String = "", var internal:
                 // don't augment input when the consumption was rolled-back
                 case ((aid, (_, aen)), st) if aen > p.toOffset =>
                     // remove the UID from the child (ew gross, there has to be a better way to do this?!)
-                    children.valuesIterator.find(_.cNumber.contains(aid)).foreach { t =>
+                    children.find(_.cNumber.contains(aid)).foreach { t =>
                         t.cNumber = None
                     }
                     st