add Chapter18

Chapter18/cib/libs/log/catalog/catalog.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <log/level.hpp>
+
+#include <cstdint>
+
+namespace sc {
+template <typename...> struct args;
+template <typename, typename T, T...> struct undefined;
+
+template <logging::level, typename> struct message {};
+template <typename> struct module_string {};
+} // namespace sc
+
+using string_id = std::uint32_t;
+using module_id = std::uint32_t;
+
+template <typename> extern auto catalog() -> string_id;
+template <typename> extern auto module() -> module_id;