feat: traversing variation trees in post-order

Author: pmbittner

src/main/java/org/variantsync/diffdetective/variation/tree/VariationNode.java

@@ -419,6 +419,17 @@ public void forAllPreorder(Consumer<T> action) {
         }
     }
 
+    /**
+     * Traverses all nodes in this subtree in postorder.
+     */
+    public void forAllPostorder(Consumer<T> action) {
+        for (var child : getChildren()) {
+            child.forAllPostorder(action);
+        }
+
+        action.accept(this.upCast());
+    }
+
     public void forMeAndMyAncestors(final Consumer<T> action) {
         action.accept(this.upCast());
         final T p = getParent();

src/main/java/org/variantsync/diffdetective/variation/tree/VariationTree.java

@@ -151,7 +151,7 @@ public VariationDiff<L> toCompletelyUnchangedVariationDiff() {
     }
 
     /**
-     * Invokes the given callback for each node in this Variation Tree in depth-first order.
+     * Invokes the given callback for each node in this Variation Tree in pre-order.
      * @param action callback
      * @return this
      */
@@ -160,6 +160,16 @@ public VariationTree<L> forAllPreorder(final Consumer<VariationTreeNode<L>> acti
         return this;
     }
 
+    /**
+     * Invokes the given callback for each node in this Variation Tree in post-order.
+     * @param action callback
+     * @return this
+     */
+    public VariationTree<L> forAllPostorder(final Consumer<VariationTreeNode<L>> action) {
+        root.forAllPostorder(action);
+        return this;
+    }
+
     /**
      * Checks whether any node in this tree satisfies the given condition.
      * The condition might not be invoked on every node in case a node is found.