move transparent hash to its own header

library/CMakeLists.txt

@@ -77,6 +77,7 @@ set(MAIN_HEADERS
     include/RemoteTools.h
     include/Signal.hpp
     include/TileTypes.h
+    include/TransHash.h
     include/Types.h
     include/VersionInfo.h
     include/VersionInfoFactory.h

library/include/DataDefs.h

@@ -37,6 +37,7 @@ distribution.
 #include "BitArray.h"
 #include "Export.h"
 #include "Format.h"
+#include "TransHash.h"
 
 struct lua_State;
 
@@ -364,30 +365,6 @@ namespace DFHack
         virtual void build_metatable(lua_State *state) const;
     };
 
-    namespace
-    {
-        template<typename ... Bases>
-        struct overload : Bases ...
-        {
-            using is_transparent = void;
-            using Bases::operator() ...;
-        };
-
-        struct char_pointer_hash
-        {
-            auto operator()(const char* ptr) const noexcept
-            {
-                return std::hash<std::string_view>{}(ptr);
-            }
-        };
-
-        using transparent_string_hash = overload<
-            std::hash<std::string>,
-            std::hash<std::string_view>,
-            char_pointer_hash
-        >;
-    }
-
 #ifdef _MSC_VER
     using virtual_ptr = void*;
 #else

library/include/TransHash.h

@@ -0,0 +1,28 @@
+#ifndef TRANS_HASH_H
+#define TRANS_HASH_H
+
+namespace
+{
+    template<typename ... Bases>
+    struct overload : Bases ...
+    {
+        using is_transparent = void;
+        using Bases::operator() ...;
+    };
+
+    struct char_pointer_hash
+    {
+        auto operator()(const char* ptr) const noexcept
+        {
+            return std::hash<std::string_view>{}(ptr);
+        }
+    };
+
+    using transparent_string_hash = overload<
+        std::hash<std::string>,
+        std::hash<std::string_view>,
+        char_pointer_hash
+    >;
+}
+
+#endif