LuaBridge: support argument references via table return

6 files changed, 594 insertions, 58 deletions

diff --git a/libs/lua/LuaBridge/LuaBridge.h b/libs/lua/LuaBridge/LuaBridge.h
index fb61340bcc..d03120ae00 100644
--- a/libs/lua/LuaBridge/LuaBridge.h
+++ b/libs/lua/LuaBridge/LuaBridge.h
@@ -77,6 +77,7 @@ class LuaRef;
 #include "detail/LuaException.h"
 #include "detail/LuaRef.h"
 #include "detail/Iterator.h"
+#include "detail/FuncArgs.h"
 
 //------------------------------------------------------------------------------
 /**
diff --git a/libs/lua/LuaBridge/detail/CFunctions.h b/libs/lua/LuaBridge/detail/CFunctions.h
index 1c0caa84ac..fa78b78fd6 100644
--- a/libs/lua/LuaBridge/detail/CFunctions.h
+++ b/libs/lua/LuaBridge/detail/CFunctions.h
@@ -378,7 +378,106 @@ struct CFunc
     }
   };
 
+  /**
+      lua_CFunction to calls for function references.
+  */
+  template <class MemFnPtr,
+            class ReturnType = typename FuncTraits <MemFnPtr>::ReturnType>
+  struct CallMemberRef
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
 
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      T* const t = Userdata::get <T> (L, 1, false);
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      Stack <ReturnType>::push (L, FuncTraits <MemFnPtr>::call (t, fnptr, args));
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 2;
+    }
+  };
+
+  template <class MemFnPtr,
+            class ReturnType = typename FuncTraits <MemFnPtr>::ReturnType>
+  struct CallConstMemberRef
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      T const* const t = Userdata::get <T> (L, 1, true);
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args(L);
+      Stack <ReturnType>::push (L, FuncTraits <MemFnPtr>::call (t, fnptr, args));
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 2;
+    }
+  };
+
+  template <class MemFnPtr, class T,
+            class ReturnType = typename FuncTraits <MemFnPtr>::ReturnType>
+  struct CallMemberRefPtr
+  {
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      boost::shared_ptr<T>* const t = Userdata::get <boost::shared_ptr<T> > (L, 1, false);
+      T* const tt = t->get();
+      if (!tt) {
+        return luaL_error (L, "shared_ptr is nil");
+      }
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      Stack <ReturnType>::push (L, FuncTraits <MemFnPtr>::call (tt, fnptr, args));
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 2;
+    }
+  };
+
+  template <class MemFnPtr, class T,
+            class ReturnType = typename FuncTraits <MemFnPtr>::ReturnType>
+  struct CallMemberRefWPtr
+  {
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      boost::weak_ptr<T>* const tw = Userdata::get <boost::weak_ptr<T> > (L, 1, false);
+      boost::shared_ptr<T> const t = tw->lock();
+      if (!t) {
+        return luaL_error (L, "cannot lock weak_ptr");
+      }
+      T* const tt = t.get();
+      if (!tt) {
+        return luaL_error (L, "weak_ptr is nil");
+      }
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      Stack <ReturnType>::push (L, FuncTraits <MemFnPtr>::call (tt, fnptr, args));
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 2;
+    }
+  };
 
   //----------------------------------------------------------------------------
   /**
@@ -466,7 +565,99 @@ struct CFunc
     }
   };
 
+  template <class MemFnPtr>
+  struct CallMemberRef <MemFnPtr, void>
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      T* const t = Userdata::get <T> (L, 1, false);
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      FuncTraits <MemFnPtr>::call (t, fnptr, args);
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 1;
+    }
+  };
+
+  template <class MemFnPtr>
+  struct CallConstMemberRef <MemFnPtr, void>
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      T const* const t = Userdata::get <T> (L, 1, true);
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      FuncTraits <MemFnPtr>::call (t, fnptr, args);
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 1;
+    }
+  };
+
+  template <class MemFnPtr, class T>
+  struct CallMemberRefPtr <MemFnPtr, T, void>
+  {
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
 
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      boost::shared_ptr<T>* const t = Userdata::get <boost::shared_ptr<T> > (L, 1, false);
+      T* const tt = t->get();
+      if (!tt) {
+        return luaL_error (L, "shared_ptr is nil");
+      }
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      FuncTraits <MemFnPtr>::call (tt, fnptr, args);
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 1;
+    }
+  };
+
+  template <class MemFnPtr, class T>
+  struct CallMemberRefWPtr <MemFnPtr, T, void>
+  {
+    typedef typename FuncTraits <MemFnPtr>::Params Params;
+
+    static int f (lua_State* L)
+    {
+      assert (isfulluserdata (L, lua_upvalueindex (1)));
+      boost::weak_ptr<T>* const tw = Userdata::get <boost::weak_ptr<T> > (L, 1, false);
+      boost::shared_ptr<T> const t = tw->lock();
+      if (!t) {
+        return luaL_error (L, "cannot lock weak_ptr");
+      }
+      T* const tt = t.get();
+      if (!tt) {
+        return luaL_error (L, "weak_ptr is nil");
+      }
+      MemFnPtr const& fnptr = *static_cast <MemFnPtr const*> (lua_touserdata (L, lua_upvalueindex (1)));
+      assert (fnptr != 0);
+      ArgList <Params, 2> args (L);
+      FuncTraits <MemFnPtr>::call (tt, fnptr, args);
+      LuaRef v (newTable (L));
+      FuncArgs <Params, 0>::refs (v, args);
+      v.push(L);
+      return 1;
+    }
+  };
 
   //--------------------------------------------------------------------------
   /**
@@ -544,6 +735,18 @@ struct CFunc
   };
 
   template <class MemFnPtr>
+  struct CallMemberRefPtrFunctionHelper
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    static void add (lua_State* L, char const* name, MemFnPtr mf)
+    {
+      new (lua_newuserdata (L, sizeof (MemFnPtr))) MemFnPtr (mf);
+      lua_pushcclosure (L, &CallMemberRefPtr <MemFnPtr, T>::f, 1);
+      rawsetfield (L, -3, name); // class table
+    }
+  };
+
+  template <class MemFnPtr>
   struct CallMemberWPtrFunctionHelper
   {
     typedef typename FuncTraits <MemFnPtr>::ClassType T;
@@ -555,6 +758,42 @@ struct CFunc
     }
   };
 
+  template <class MemFnPtr>
+  struct CallMemberRefWPtrFunctionHelper
+  {
+    typedef typename FuncTraits <MemFnPtr>::ClassType T;
+    static void add (lua_State* L, char const* name, MemFnPtr mf)
+    {
+      new (lua_newuserdata (L, sizeof (MemFnPtr))) MemFnPtr (mf);
+      lua_pushcclosure (L, &CallMemberRefWPtr <MemFnPtr, T>::f, 1);
+      rawsetfield (L, -3, name); // class table
+    }
+  };
+
+  template <class MemFnPtr, bool isConst>
+  struct CallMemberRefFunctionHelper
+  {
+    static void add (lua_State* L, char const* name, MemFnPtr mf)
+    {
+      new (lua_newuserdata (L, sizeof (MemFnPtr))) MemFnPtr (mf);
+      lua_pushcclosure (L, &CallConstMemberRef <MemFnPtr>::f, 1);
+      lua_pushvalue (L, -1);
+      rawsetfield (L, -5, name); // const table
+      rawsetfield (L, -3, name); // class table
+    }
+  };
+
+  template <class MemFnPtr>
+  struct CallMemberRefFunctionHelper <MemFnPtr, false>
+  {
+    static void add (lua_State* L, char const* name, MemFnPtr mf)
+    {
+      new (lua_newuserdata (L, sizeof (MemFnPtr))) MemFnPtr (mf);
+      lua_pushcclosure (L, &CallMemberRef <MemFnPtr>::f, 1);
+      rawsetfield (L, -3, name); // class table
+    }
+  };
+
   //--------------------------------------------------------------------------
   /**
       __gc metamethod for a class.
diff --git a/libs/lua/LuaBridge/detail/FuncArgs.h b/libs/lua/LuaBridge/detail/FuncArgs.h
new file mode 100644
index 0000000000..38d0543175
--- /dev/null
+++ b/libs/lua/LuaBridge/detail/FuncArgs.h
@@ -0,0 +1,51 @@
+//------------------------------------------------------------------------------
+/*
+  https://github.com/vinniefalco/LuaBridge
+
+  Copyright 2016, Robin Gareus <robin@gareus.org>
+  Copyright 2012, Vinnie Falco <vinnie.falco@gmail.com>
+
+  License: The MIT License (http://www.opensource.org/licenses/mit-license.php)
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+*/
+//==============================================================================
+
+template <typename List, int Start = 1>
+struct FuncArgs
+{
+};
+
+template <int Start>
+struct FuncArgs<None, Start>
+{
+  static void refs (LuaRef, TypeListValues <None>)
+	{
+	}
+};
+
+template <typename Head, typename Tail, int Start>
+struct FuncArgs<TypeList <Head, Tail>, Start >
+{
+  static void refs (LuaRef l, TypeListValues <TypeList <Head, Tail> > tvl)
+	{
+		l[Start + 1] = tvl.hd;
+    FuncArgs <Tail, Start + 1>::refs (l, tvl.tl);
+	}
+};
diff --git a/libs/lua/LuaBridge/detail/FuncTraits.h b/libs/lua/LuaBridge/detail/FuncTraits.h
index a99cbab299..c99d028e86 100644
--- a/libs/lua/LuaBridge/detail/FuncTraits.h
+++ b/libs/lua/LuaBridge/detail/FuncTraits.h
@@ -81,7 +81,7 @@ struct FuncTraits <R (*) (P1), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd);
   }
@@ -94,7 +94,7 @@ struct FuncTraits <R (*) (P1, P2), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd);
   }
@@ -107,7 +107,7 @@ struct FuncTraits <R (*) (P1, P2, P3), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -120,7 +120,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -133,7 +133,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd);
   }
@@ -146,7 +146,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5,  TypeList <P6> > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -159,7 +159,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6, P7), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -172,7 +172,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6, P7, P8), D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -204,7 +204,7 @@ struct FuncTraits <R (T::*) (P1), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params> &tvl)
   {
     return (obj->*fp)(tvl.hd);
   }
@@ -219,7 +219,7 @@ struct FuncTraits <R (T::*) (P1, P2), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd);
   }
@@ -234,7 +234,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -249,7 +249,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -264,7 +264,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd);
   }
@@ -279,7 +279,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6> > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -294,7 +294,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -309,7 +309,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7, P8), D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -341,7 +341,7 @@ struct FuncTraits <R (T::*) (P1) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd);
   }
@@ -357,7 +357,7 @@ struct FuncTraits <R (T::*) (P1, P2) const, D>
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
   static R call (T const* obj, R (T::*fp) (P1, P2) const,
-    TypeListValues <Params> tvl)
+    TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd);
   }
@@ -372,7 +372,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -387,7 +387,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -402,7 +402,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd);
   }
@@ -417,7 +417,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6> > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -432,7 +432,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -447,7 +447,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7, P8) const, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -477,7 +477,7 @@ struct FuncTraits <R (*) (P1) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd);
   }
@@ -490,7 +490,7 @@ struct FuncTraits <R (*) (P1, P2) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd);
   }
@@ -503,7 +503,7 @@ struct FuncTraits <R (*) (P1, P2, P3) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -516,7 +516,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -529,7 +529,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd);
   }
@@ -542,7 +542,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5,  TypeList <P6> > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -555,7 +555,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6, P7) LUABRIDGE_THROWSPEC, D>
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -568,7 +568,7 @@ struct FuncTraits <R (*) (P1, P2, P3, P4, P5, P6, P7, P8) LUABRIDGE_THROWSPEC, D
   typedef D DeclType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (D fp, TypeListValues <Params> tvl)
+  static R call (D fp, TypeListValues <Params>& tvl)
   {
     return fp (tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -600,7 +600,7 @@ struct FuncTraits <R (T::*) (P1) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd);
   }
@@ -615,7 +615,7 @@ struct FuncTraits <R (T::*) (P1, P2) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd);
   }
@@ -630,7 +630,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -645,7 +645,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -660,7 +660,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd);
   }
@@ -675,7 +675,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6> > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -690,7 +690,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7) LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -705,7 +705,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7, P8) LUABRIDGE_THROWSPEC
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (T* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -737,7 +737,7 @@ struct FuncTraits <R (T::*) (P1) const LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1> Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd);
   }
@@ -752,7 +752,7 @@ struct FuncTraits <R (T::*) (P1, P2) const LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2> > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd);
   }
@@ -767,7 +767,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3) const LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3> > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd);
   }
@@ -782,7 +782,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4) const LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4> > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd);
   }
@@ -797,7 +797,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5) const LUABRIDGE_THROWSPEC, D>
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5> > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd,
       tvl.tl.tl.tl.tl.hd);
@@ -813,7 +813,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6) const LUABRIDGE_THROWSPEC,
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6> > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd);
   }
@@ -828,7 +828,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7) const LUABRIDGE_THROWSP
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7> > > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd);
   }
@@ -843,7 +843,7 @@ struct FuncTraits <R (T::*) (P1, P2, P3, P4, P5, P6, P7, P8) const LUABRIDGE_THR
   typedef T ClassType;
   typedef R ReturnType;
   typedef TypeList <P1, TypeList <P2, TypeList <P3, TypeList <P4, TypeList <P5, TypeList <P6, TypeList <P7, TypeList <P8> > > > > > > > Params;
-  static R call (T const* obj, D fp, TypeListValues <Params> tvl)
+  static R call (T const* obj, D fp, TypeListValues <Params>& tvl)
   {
     return (obj->*fp)(tvl.hd, tvl.tl.hd, tvl.tl.tl.hd, tvl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.hd, tvl.tl.tl.tl.tl.tl.tl.tl.hd);
   }
diff --git a/libs/lua/LuaBridge/detail/Namespace.h b/libs/lua/LuaBridge/detail/Namespace.h
index 464d9d08a0..eae70dd41e 100644
--- a/libs/lua/LuaBridge/detail/Namespace.h
+++ b/libs/lua/LuaBridge/detail/Namespace.h
@@ -815,6 +815,13 @@ private:
       return *this;
     }
 
+    template <class MemFn>
+    Class <T>& addRefFunction (char const* name, MemFn mf)
+    {
+      CFunc::CallMemberRefFunctionHelper <MemFn, FuncTraits <MemFn>::isConstMemberFunction>::add (L, name, mf);
+      return *this;
+    }
+
 
     //--------------------------------------------------------------------------
     /**
@@ -1032,6 +1039,17 @@ private:
     }
 
     template <class MemFn>
+    WSPtrClass <T>& addRefFunction (char const* name, MemFn mf)
+    {
+      set_weak_class ();
+      CFunc::CallMemberRefWPtrFunctionHelper <MemFn>::add (L, name, mf);
+
+      set_shared_class ();
+      CFunc::CallMemberRefPtrFunctionHelper <MemFn>::add (L, name, mf);
+      return *this;
+    }
+
+    template <class MemFn>
     WSPtrClass <T>& addConstructor ()
     {
       set_weak_class ();
diff --git a/libs/lua/LuaBridge/detail/Stack.h b/libs/lua/LuaBridge/detail/Stack.h
index a569093ad1..0d4919be27 100644
--- a/libs/lua/LuaBridge/detail/Stack.h
+++ b/libs/lua/LuaBridge/detail/Stack.h
@@ -61,6 +61,31 @@ struct Stack <lua_CFunction>
 
 //------------------------------------------------------------------------------
 /**
+    Stack specialization for passing references to built-in types.
+
+    This allows to call functions using primitives, but
+    the value assigned by the C++ function is *lost*.
+
+    http://sourceforge.net/p/luabind/mailman/message/32692027/
+
+    Alternatives:
+     - wrap all C++ function that have non const reference arguments
+    (cleanest solution)
+
+     - use a struct to wrap the value (not a primitive)
+    (needs major work to special case arguments in CFunc::)
+
+     - wrap the function and provide the assigned value
+     as addition return values
+
+    Either would place hard constraints on the lua code though.
+
+    We currently only need this for Ardour::Editor::do_import() framecnt_t&
+    and the returned position is not important.
+*/
+
+//------------------------------------------------------------------------------
+/**
     Stack specialization for `int`.
 */
 template <>
@@ -90,6 +115,23 @@ struct Stack <int const&>
     return static_cast <int > (luaL_checknumber (L, index));
   }
 };
+
+template <>
+struct Stack <int &>
+{
+  static inline void push (lua_State* L, int &value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline int& get (lua_State* L, int index)
+  {
+    int l = static_cast <int> (luaL_checknumber (L, index));
+    boost::reference_wrapper<int> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `unsigned int`.
@@ -122,6 +164,22 @@ struct Stack <unsigned int const&>
   }
 };
 
+template <>
+struct Stack <unsigned int &>
+{
+  static inline void push (lua_State* L, unsigned int& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline unsigned int& get (lua_State* L, int index)
+  {
+    unsigned int l = static_cast <unsigned int> (luaL_checknumber (L, index));
+    boost::reference_wrapper<unsigned int> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `unsigned char`.
@@ -154,6 +212,22 @@ struct Stack <unsigned char const&>
   }
 };
 
+template <>
+struct Stack <unsigned char &>
+{
+  static inline void push (lua_State* L, unsigned char& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline unsigned char& get (lua_State* L, int index)
+  {
+    unsigned char l = static_cast <unsigned char> (luaL_checknumber (L, index));
+    boost::reference_wrapper<unsigned char> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `short`.
@@ -186,6 +260,22 @@ struct Stack <short const&>
   }
 };
 
+template <>
+struct Stack <short &>
+{
+  static inline void push (lua_State* L, short& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline short& get (lua_State* L, int index)
+  {
+    short l = static_cast <short> (luaL_checknumber (L, index));
+    boost::reference_wrapper<short> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `unsigned short`.
@@ -218,6 +308,22 @@ struct Stack <unsigned short const&>
   }
 };
 
+template <>
+struct Stack <unsigned short &>
+{
+  static inline void push (lua_State* L, unsigned short& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline unsigned short& get (lua_State* L, int index)
+  {
+    unsigned short l = static_cast <unsigned short> (luaL_checknumber (L, index));
+    boost::reference_wrapper<unsigned short> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `long`.
@@ -250,6 +356,22 @@ struct Stack <long const&>
   }
 };
 
+template <>
+struct Stack <long &>
+{
+  static inline void push (lua_State* L, long& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline long& get (lua_State* L, int index)
+  {
+    long l = static_cast <long> (luaL_checknumber (L, index));
+    boost::reference_wrapper<long> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `unsigned long`.
@@ -282,6 +404,22 @@ struct Stack <unsigned long const&>
   }
 };
 
+template <>
+struct Stack <unsigned long &>
+{
+  static inline void push (lua_State* L, unsigned long& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline unsigned long& get (lua_State* L, int index)
+  {
+    unsigned long l = static_cast <unsigned long> (luaL_checknumber (L, index));
+    boost::reference_wrapper<unsigned long> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `long long`.
@@ -314,6 +452,22 @@ struct Stack <long long const&>
   }
 };
 
+template <>
+struct Stack <long long &>
+{
+  static inline void push (lua_State* L, long long& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline long long& get (lua_State* L, int index)
+  {
+    long long l = static_cast <long long> (luaL_checknumber (L, index));
+    boost::reference_wrapper<long long> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `unsigned long long`.
@@ -378,6 +532,22 @@ struct Stack <float const&>
   }
 };
 
+template <>
+struct Stack <float &>
+{
+  static inline void push (lua_State* L, float& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline float& get (lua_State* L, int index)
+  {
+    float l = static_cast <float> (luaL_checknumber (L, index));
+    boost::reference_wrapper<float> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `double`.
@@ -408,6 +578,21 @@ template <> struct Stack <double const&>
   }
 };
 
+template <> struct Stack <double &>
+{
+  static inline void push (lua_State* L, double& value)
+  {
+    lua_pushnumber (L, static_cast <lua_Number> (value));
+  }
+
+  static inline double& get (lua_State* L, int index)
+  {
+    double l = static_cast <double> (luaL_checknumber (L, index));
+    boost::reference_wrapper<double> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `bool`.
@@ -438,6 +623,21 @@ struct Stack <bool const&> {
   }
 };
 
+template <>
+struct Stack <bool &> {
+  static inline void push (lua_State* L, bool& value)
+  {
+    lua_pushboolean (L, value ? 1 : 0);
+  }
+
+  static inline bool& get (lua_State* L, int index)
+  {
+    bool l = lua_toboolean (L, index) ? true : false;
+    boost::reference_wrapper<bool> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `char`.
@@ -472,12 +672,8 @@ struct Stack <char const&>
   }
 };
 
-//------------------------------------------------------------------------------
-/**
-    Stack specialization for `float`.
-*/
 template <>
-struct Stack <char const*>
+struct Stack <char const *>
 {
   static inline void push (lua_State* L, char const* str)
   {
@@ -487,12 +683,29 @@ struct Stack <char const*>
       lua_pushnil (L);
   }
 
-  static inline char const* get (lua_State* L, int index)
+  static inline char const *get (lua_State* L, int index)
   {
     return lua_isnil (L, index) ? 0 : luaL_checkstring (L, index);
   }
 };
 
+template <>
+struct Stack <char &>
+{
+  static inline void push (lua_State* L, char& value)
+  {
+    char str [2] = { value, 0 };
+    lua_pushstring (L, str);
+  }
+
+  static inline char get (lua_State* L, int index)
+  {
+    char l = luaL_checkstring (L, index) [0];
+    boost::reference_wrapper<char> r (l);
+    return r.get();
+  }
+};
+
 //------------------------------------------------------------------------------
 /**
     Stack specialization for `std::string`.
@@ -513,10 +726,6 @@ struct Stack <std::string>
   }
 };
 
-//------------------------------------------------------------------------------
-/**
-    Stack specialization for `std::string const&`.
-*/
 template <>
 struct Stack <std::string const&>
 {
@@ -532,3 +741,21 @@ struct Stack <std::string const&>
     return std::string (str, len);
   }
 };
+
+template <>
+struct Stack <std::string &>
+{
+  static inline void push (lua_State* L, std::string& str)
+  {
+    lua_pushlstring (L, str.c_str (), str.size());
+  }
+
+  static inline std::string& get (lua_State* L, int index)
+  {
+    size_t len;
+    const char *str = luaL_checklstring(L, index, &len);
+    std::string l (str, len);
+    boost::reference_wrapper<std::string> r (l);
+    return r.get();
+  }
+};