--******************************************************************************
--*                                                                            *
--*  File:        FunctionProtection.lua                Revision:  1.0         *
--*                                                                            *
--*  Purpose:     protects Lua functions from being overwritten                *
--*                                                                            *
--*  Creation:    04.04.2002                   Last Modification:  04.04.2002  *
--*                                                                            *
--*  Platform:    IBM-compatible PC running Windows 98SE                       *
--*                                                                            *
--*  Environment: Lua 4.0, TkLua 4.0                                           *
--*                                                                            *
--*  Author:      Andreas Rozek           Phone:  ++49 (711) 6770682           *
--*               Kirschblütenweg 15      Fax:    -                            *
--*             D-70569 Stuttgart         EMail:  Andreas.Rozek@T-Online.De    *
--*               Germany                                                      *
--*                                                                            *
--*  URL:         http://www.Andreas-Rozek.de/                                 *
--*                                                                            *
--*  Copyright:   the software is published under the "GNU Lesser General Pub- *
--*               lic  License" (see "http://www.fsf.org/copyleft/lesser.html" *
--*               for additional information)                                  *
--*                                                                            *
--*  Comments:    this code was mainly taken from                              *
--*                                                                            *
--*                 http://www.lua.org/faq.html#3.3                            *
--*                                                                            *
--******************************************************************************

--**** do not execute this script more often than once ****

  if (type(protectFunction) == "function") then return nil; end;

--******************************************************************************
--*                                                                            *
--* protectFunction                  protects functions from being overwritten *
--*                                                                            *
--******************************************************************************

  function protectFunction (FunctionName)
    error("unable to redefine function \""..protectFunction.."\"");
  end;

  settagmethod(tag(protectFunction), "setglobal", protectFunction);