m_index for Parser

src/Parser.cpp

@@ -31,3 +31,18 @@ Parser::ErrorOr<ExprNode> Parser::walk_expr()
 {
     return ErrorOr<ExprNode>(new ExprNode()); // constructor does not want to accept a shared_ptr<T> in the argument list, thats why im not using make_shared here
 }
+
+Parser::ErrorOr<NumberNode> Parser::walk_number()
+{
+    return ErrorOr<NumberNode>(new NumberNode());
+}
+
+void Parser::save_current_position()
+{
+    saved_m_index = m_index;
+}
+
+void Parser::restore_current_position()
+{
+    m_index = saved_m_index;
+}

src/Parser.h

@@ -38,6 +38,12 @@ private:
 
     ErrorOr<ExprNode> walk_expr();
     ErrorOr<NumberNode> walk_number();
+
+    int m_index;
+    int saved_m_index;
+
+    void save_current_position();
+    void restore_current_position();
 public:
     ~Parser();