diff --git a/src/leaf_data_type.hpp b/src/leaf_data_type.hpp
new file mode 100644
index 0000000..66f4522
--- /dev/null
+++ b/src/leaf_data_type.hpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2020 CESNET, https://photonics.cesnet.cz/
+ *
+ * Written by Václav Kubernát <kubernat@cesnet.cz>
+ *
+*/
+
+#pragma once
+#include <memory>
+#include <set>
+#include <string>
+#include <variant>
+
+struct enum_;
+struct identityRef_;
+
+namespace yang {
+struct String {
+    bool operator==(const String&) const;
+};
+struct Decimal {
+    bool operator==(const Decimal&) const;
+};
+struct Bool {
+    bool operator==(const Bool&) const;
+};
+struct Int8 {
+    bool operator==(const Int8&) const;
+};
+struct Uint8 {
+    bool operator==(const Uint8&) const;
+};
+struct Int16 {
+    bool operator==(const Int16&) const;
+};
+struct Uint16 {
+    bool operator==(const Uint16&) const;
+};
+struct Int32 {
+    bool operator==(const Int32&) const;
+};
+struct Uint32 {
+    bool operator==(const Uint32&) const;
+};
+struct Int64 {
+    bool operator==(const Int64&) const;
+};
+struct Uint64 {
+    bool operator==(const Uint64&) const;
+};
+struct Binary {
+    bool operator==(const Binary&) const;
+};
+struct Enum {
+    Enum(std::set<enum_>&& values);
+    bool operator==(const Enum& other) const;
+    std::set<enum_> m_allowedValues;
+};
+struct IdentityRef {
+    IdentityRef(std::set<identityRef_>&& list);
+    bool operator==(const IdentityRef& other) const;
+    std::set<identityRef_> m_allowedValues;
+};
+struct LeafRef;
+using LeafDataType = std::variant<
+    yang::String,
+    yang::Decimal,
+    yang::Bool,
+    yang::Int8,
+    yang::Uint8,
+    yang::Int16,
+    yang::Uint16,
+    yang::Int32,
+    yang::Uint32,
+    yang::Int64,
+    yang::Uint64,
+    yang::Enum,
+    yang::Binary,
+    yang::IdentityRef,
+    yang::LeafRef
+>;
+struct LeafRef {
+    LeafRef(const LeafRef& src);
+    LeafRef(const std::string& xpath, std::unique_ptr<LeafDataType>&& type);
+    bool operator==(const LeafRef& other) const;
+    std::string m_targetXPath;
+    std::unique_ptr<LeafDataType> m_targetType;
+};
+}