diff --git a/include/cppast/diagnostic_logger.hpp b/include/cppast/diagnostic_logger.hpp
new file mode 100644
index 0000000..7748ac0
--- /dev/null
+++ b/include/cppast/diagnostic_logger.hpp
@@ -0,0 +1,71 @@
+// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
+// This file is subject to the license terms in the LICENSE file
+// found in the top-level directory of this distribution.
+
+#ifndef CPPAST_DIAGNOSTIC_LOGGER_HPP_INCLUDED
+#define CPPAST_DIAGNOSTIC_LOGGER_HPP_INCLUDED
+
+#include <type_safe/reference.hpp>
+
+#include <cppast/diagnostic.hpp>
+
+namespace cppast
+{
+    /// Base class for a [cppast::diagnostic]() logger.
+    ///
+    /// Its task is controlling how diagnostic are being displayed.
+    class diagnostic_logger
+    {
+    public:
+        /// \effects Creates it either as verbose or not.
+        explicit diagnostic_logger(bool is_verbose = false) noexcept : verbose_(is_verbose)
+        {
+        }
+
+        diagnostic_logger(const diagnostic_logger&) = delete;
+        diagnostic_logger& operator=(const diagnostic_logger&) = delete;
+        virtual ~diagnostic_logger() noexcept                  = default;
+
+        /// \effects Logs the diagnostic by invoking the `do_log()` member function.
+        /// \returns Whether or not the diagnostic was logged.
+        /// \notes `source` points to a string literal that gives additional context to what generates the message.
+        bool log(const char* source, const diagnostic& d) const;
+
+        /// \effects Sets whether or not the logger prints debugging diagnostics.
+        void set_verbose(bool value) noexcept
+        {
+            verbose_ = value;
+        }
+
+        /// \returns Whether or not the logger prints debugging diagnostics.
+        bool is_verbose() const noexcept
+        {
+            return verbose_;
+        }
+
+    private:
+        virtual bool do_log(const char* source, const diagnostic& d) const = 0;
+
+        bool verbose_;
+    };
+
+    /// \returns The default logger object.
+    type_safe::object_ref<const diagnostic_logger> default_logger() noexcept;
+
+    /// \returns The default verbose logger object.
+    type_safe::object_ref<const diagnostic_logger> default_verbose_logger() noexcept;
+
+    /// A [cppast::diagnostic_logger]() that logs to `stderr`.
+    ///
+    /// It prints all diagnostics in an implementation-defined format.
+    class stderr_diagnostic_logger final : public diagnostic_logger
+    {
+    public:
+        using diagnostic_logger::diagnostic_logger;
+
+    private:
+        bool do_log(const char* source, const diagnostic& d) const override;
+    };
+} // namespace cppast
+
+#endif // CPPAST_DIAGNOSTIC_LOGGER_HPP_INCLUDED
diff --git a/include/cppast/parser.hpp b/include/cppast/parser.hpp
index b1723c5..84badba 100644
--- a/include/cppast/parser.hpp
+++ b/include/cppast/parser.hpp
@@ -10,67 +10,11 @@
 #include <cppast/compile_config.hpp>
 #include <cppast/cpp_file.hpp>
 #include <cppast/cpp_preprocessor.hpp>
+#include <cppast/diagnostic_logger.hpp>
 
 namespace cppast
 {
     class cpp_entity_index;
-    struct diagnostic;
-
-    /// Base class for a [cppast::diagnostic]() logger.
-    ///
-    /// Its task is controlling how diagnostic are being displayed.
-    class diagnostic_logger
-    {
-    public:
-        /// \effects Creates it either as verbose or not.
-        explicit diagnostic_logger(bool is_verbose = false) noexcept : verbose_(is_verbose)
-        {
-        }
-
-        diagnostic_logger(const diagnostic_logger&) = delete;
-        diagnostic_logger& operator=(const diagnostic_logger&) = delete;
-        virtual ~diagnostic_logger() noexcept                  = default;
-
-        /// \effects Logs the diagnostic by invoking the `do_log()` member function.
-        /// \returns Whether or not the diagnostic was logged.
-        /// \notes `source` points to a string literal that gives additional context to what generates the message.
-        bool log(const char* source, const diagnostic& d) const;
-
-        /// \effects Sets whether or not the logger prints debugging diagnostics.
-        void set_verbose(bool value) noexcept
-        {
-            verbose_ = value;
-        }
-
-        /// \returns Whether or not the logger prints debugging diagnostics.
-        bool is_verbose() const noexcept
-        {
-            return verbose_;
-        }
-
-    private:
-        virtual bool do_log(const char* source, const diagnostic& d) const = 0;
-
-        bool verbose_;
-    };
-
-    /// \returns The default logger object.
-    type_safe::object_ref<const diagnostic_logger> default_logger() noexcept;
-
-    /// \returns The default verbose logger object.
-    type_safe::object_ref<const diagnostic_logger> default_verbose_logger() noexcept;
-
-    /// A [cppast::diagnostic_logger]() that logs to `stderr`.
-    ///
-    /// It prints all diagnostics in an implementation-defined format.
-    class stderr_diagnostic_logger final : public diagnostic_logger
-    {
-    public:
-        using diagnostic_logger::diagnostic_logger;
-
-    private:
-        bool do_log(const char* source, const diagnostic& d) const override;
-    };
 
     /// Base class for a parser.
     ///
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 72a9b83..8f2af0c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -42,6 +42,7 @@ set(header
     ../include/cppast/cpp_variable_base.hpp
     ../include/cppast/cpp_variable_template.hpp
     ../include/cppast/diagnostic.hpp
+    ../include/cppast/diagnostic_logger.hpp
     ../include/cppast/libclang_parser.hpp
     ../include/cppast/parser.hpp
     ../include/cppast/visitor.hpp)
@@ -71,7 +72,7 @@ set(source
         cpp_type_alias.cpp
         cpp_variable.cpp
         cpp_variable_template.cpp
-        parser.cpp
+        diagnostic_logger.cpp
         visitor.cpp)
 set(libclang_source
         libclang/class_parser.cpp
diff --git a/src/parser.cpp b/src/diagnostic_logger.cpp
similarity index 95%
rename from src/parser.cpp
rename to src/diagnostic_logger.cpp
index 172f628..64fd823 100644
--- a/src/parser.cpp
+++ b/src/diagnostic_logger.cpp
@@ -2,13 +2,11 @@
 // This file is subject to the license terms in the LICENSE file
 // found in the top-level directory of this distribution.
 
-#include <cppast/parser.hpp>
+#include <cppast/diagnostic_logger.hpp>
 
 #include <cstdio>
 #include <mutex>
 
-#include <cppast/diagnostic.hpp>
-
 using namespace cppast;
 
 bool diagnostic_logger::log(const char* source, const diagnostic& d) const