Add ObservableAstIterator#collectAll shorthand

core/src/main/kotlin/eu/iamgio/quarkdown/ast/iterator/ObservableAstIterator.kt

@@ -22,6 +22,7 @@ class ObservableAstIterator : AstIterator {
     /**
      * Registers a hook that will be called when a node of type [T] is visited.
      * @param hook action to be called, with the visited node as parameter
+     * @param T desired node type
      * @return this for concatenation
      */
     inline fun <reified T : Node> on(noinline hook: (T) -> Unit): ObservableAstIterator =
@@ -39,6 +40,16 @@ class ObservableAstIterator : AstIterator {
             onFinishedHooks.add(hook)
         }
 
+    /**
+     * Collects all the visited nodes of type [T] into a collection.
+     * @param T node type
+     * @return an ordered list (DFS order) containing all the visited nodes of type [T] in the tree
+     */
+    inline fun <reified T : Node> collectAll(): List<T> =
+        mutableListOf<T>().apply {
+            on<T>(::add)
+        }
+
     /**
      * Attaches a hook to this iterator.
      * @param hook hook to attach

core/src/main/kotlin/eu/iamgio/quarkdown/context/hooks/TableOfContentsGeneratorHook.kt

@@ -12,10 +12,7 @@ import eu.iamgio.quarkdown.context.toc.TableOfContents
  */
 class TableOfContentsGeneratorHook(private val context: MutableContext) : AstIteratorHook {
     override fun attach(iterator: ObservableAstIterator) {
-        val headings = mutableListOf<Heading>()
-
-        // Collecting headings.
-        iterator.on<Heading> { headings += it }
+        val headings = iterator.collectAll<Heading>()
 
         // Generation.
         iterator.onFinished {