1 files changed, 23 insertions, 9 deletions
diff --git a/grammer.cpp b/grammer.cpp
index 896a928..dc65876 100644
--- a/grammer.cpp
+++ b/grammer.cpp
@@ -193,7 +193,6 @@ void Compiler::AddFirstNode()
 
 bool Compiler::AddRootNode()
 {
- std::cout << "AddRootNode()" << std::endl;
  if (nodes.size() == 0) {
   AddFirstNode();
  } else {
@@ -237,16 +236,18 @@ bool Compiler::AddRootNode()
   // keep tokens_used as is
  }
 
+ DumpTree();
  return true;
 }
 
+// Go back one step: Remove Node or Token
 void Compiler::RemoveLastNode()
 {
  TreeNode& node {nodes.back()};
  index_t node_id = node.node_id;
  
  if (node_id == root_node_id) { // No parent -> remove root
-  if (node.child_ids.empty()) { // No children -> now empty
+  if (node.child_ids.empty()) { // No children -> now tree is empty
    clear();
   } else if (node.child_ids.size() == 1) { // One child: removing possible
    if (!ChildIdIsToken(node.child_ids[0])) {
@@ -254,6 +255,7 @@ void Compiler::RemoveLastNode()
     root_node_id = node.child_ids[0];
    }
    nodes.pop_back();
+   std::cout << "Removing " << nodes.back().type << "(" << nodes.back().node_id << ")" << std::endl;
   } else {
    DumpTree();
    throw std::runtime_error("Backtrack not possible: Root not empty"); // ICE
@@ -265,9 +267,16 @@ void Compiler::RemoveLastNode()
    throw std::runtime_error("Backtrack: Bad child nodes"); // ICE
   parent.child_ids.pop_back();
   nodes.pop_back();
+ } else if (ChildIdIsToken(node.child_ids.back())) {
+  node.child_ids.pop_back();
+  if (tokens_used > 0)
+   tokens_used--;
+  else
+   throw std::runtime_error("Parse error at "s + std::to_string(node_id) + " ("s + node.type + ")"s);
  } else { // In the middle
-  throw std::runtime_error("Backtrack in the middle of the tree."); // ICE
+  throw std::runtime_error("Backtrack in the middle of the tree: "s + std::to_string(node_id) + " ("s + node.type + ")"s); // ICE
  }
+ DumpTree();
 }
 
 // Change type of last node according to alternatives
@@ -406,11 +415,17 @@ bool Compiler::FillTree()
 
  while (!subTreeIsComplete(root_node_id, to_fill)) {
   auto& node {nodes[to_fill]};
-  auto list = GetPath(bnf[node.type][node.variant][node.child_ids.size()], tokens[tokens_used].type);
-  if (list.size() > 0) {
-   AddPath(list, to_fill);
-  } else {
-   return false;
+  std::string next_child {bnf[node.type][node.variant][node.child_ids.size()]};
+  if (next_child == tokens[tokens_used].type) { // add token directly
+   node.child_ids.push_back(ChildIdFromTokenId(tokens_used));
+   tokens_used++;
+  } else { // add inner nodes
+   auto list = GetPath(next_child, tokens[tokens_used].type);
+   if (list.size() > 0) {
+    AddPath(list, to_fill);
+   } else {
+    return false;
+   }
   }
  }
  return true;
@@ -429,7 +444,6 @@ std::pair<index_t, std::vector<TreeNode>> Compiler::compile(std::vector<Token> T
   throw std::runtime_error("No tokens!");
 
  while (!treeIsComplete()) {
-  DumpTree();
   if (!FillTree()) {
    TrackBack();
   } else if (!AddRootNode()) {