add lua/C++ dynamic_cast<>

libs/lua/LuaBridge/detail/CFunctions.h

@@ -379,6 +379,29 @@ struct CFunc
   };
 
 
+  template <class T, class R>
+  struct CastClass
+  {
+    static int f (lua_State* L)
+    {
+      T * const t = Userdata::get <T> (L, 1, false );
+      Stack <R*>::push (L, dynamic_cast<R*>(t));
+      return 1;
+    }
+  };
+
+  template <class T, class R>
+  struct CastConstClass
+  {
+    static int f (lua_State* L)
+    {
+      T const* const t = Userdata::get <T> (L, 1, true);
+      Stack <R const*>::push (L, dynamic_cast<R const*>(t));
+      return 1;
+    }
+  };
+
+
   template <class T>
   struct PtrNullCheck
   {

libs/lua/LuaBridge/detail/Namespace.h

@@ -1048,6 +1048,22 @@ private:
       return *this;
     }
 
+    template <class U>
+    Class <T>& addCast (char const* name)
+    {
+      PRINTDOC("Cast", _name << name,
+          type_name< U >(),
+          type_name< U >() << " (" << type_name< T >() << "::*)()")
+
+      assert (lua_istable (L, -1));
+      lua_pushcclosure (L, &CFunc::CastClass <T, U>::f, 0);
+      rawsetfield (L, -3, name); // class table
+
+      lua_pushcclosure (L, &CFunc::CastConstClass <T, U>::f, 0);
+      rawsetfield (L, -4, name); // const table
+      return *this;
+    }
+
   };
 
   /** C Array to/from table */

tools/fmt-luadoc.php

@@ -384,6 +384,7 @@ foreach ($doc as $b) {
 			'cand' => canonical_decl ($b)
 		);
 		break;
+	case "Cast":
 	case "Weak/Shared Pointer Cast":
 		checkclass ($b);
 		$classlist[luafn2class ($b['lua'])]['cast'][] = array (