diff --git a/src/schema.hpp b/src/schema.hpp
new file mode 100644
index 0000000..a414dc9
--- /dev/null
+++ b/src/schema.hpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2018 CESNET, https://photonics.cesnet.cz/
+ * Copyright (C) 2018 FIT CVUT, https://fit.cvut.cz/
+ *
+ * Written by Václav Kubernát <kubervac@fit.cvut.cz>
+ *
+*/
+
+#pragma once
+
+#include <boost/variant.hpp>
+#include <set>
+#include <stdexcept>
+#include <unordered_map>
+#include "ast.hpp"
+
+namespace yang {
+struct container {
+};
+struct list {
+    std::set<std::string> m_keys;
+};
+}
+
+struct nodeToString : public boost::static_visitor<std::string> {
+    std::string operator()(const nodeup_&) const
+    {
+        return "..";
+    }
+    template <class T>
+    std::string operator()(const T& node) const
+    {
+        return node.m_name;
+    }
+};
+
+using NodeType = boost::variant<yang::container, yang::list>;
+
+
+class InvalidNodeException : public std::invalid_argument {
+public:
+    using std::invalid_argument::invalid_argument;
+    ~InvalidNodeException() override;
+};
+
+/*! \class Schema
+ *     \brief The class representing the schema, that the user traverses.
+ *         */
+class Schema {
+public:
+    Schema();
+    bool nodeExists(const std::string& location, const std::string& name) const;
+
+    bool isContainer(const path_& location, const std::string& name) const;
+    void addContainer(const std::string& location, const std::string& name);
+    const std::set<std::string>& listKeys(const path_& location, const std::string& name) const;
+    bool listHasKey(const path_& location, const std::string& name, const std::string& key) const;
+    bool isList(const path_& location, const std::string& name) const;
+    void addList(const std::string& location, const std::string& name, const std::set<std::string>& keys);
+
+private:
+    const std::unordered_map<std::string, NodeType>& children(const std::string& name) const;
+
+    std::unordered_map<std::string, std::unordered_map<std::string, NodeType>> m_nodes;
+};