gtk2hs-buildtools-0.9: hierarchyGen/Hierarchy.chs.template

{-# OPTIONS_HADDOCK hide #-}
-- -*-haskell-*-
-- -------------------- automatically generated file - do not edit ----------
--  Object hierarchy for the GIMP Toolkit (GTK) Binding for Haskell
--
--  Author : Axel Simon
--
--  Copyright (C) 2001-2005 Axel Simon
--
--  This library is free software; you can redistribute it and/or
--  modify it under the terms of the GNU Lesser General Public
--  License as published by the Free Software Foundation; either
--  version 2.1 of the License, or (at your option) any later version.
--
--  This library is distributed in the hope that it will be useful,
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
--  Lesser General Public License for more details.
--
-- #hide

-- |
-- Maintainer  : gtk2hs-users\@lists.sourceforge.net
-- Stability   : provisional
-- Portability : portable (depends on GHC)
--
-- This file reflects the Gtk+ object hierarchy in terms of Haskell classes.
--
-- Note: the mk... functions were originally meant to simply be an alias
-- for the constructor. However, in order to communicate the destructor
-- of an object to objectNew, the mk... functions are now a tuple containing
-- Haskell constructor and the destructor function pointer. This hack avoids
-- changing all modules that simply pass mk... to objectNew.
--
module @MODULE_NAME@ (
@MODULE_EXPORTS@
  ) where

import Foreign.ForeignPtr (ForeignPtr, castForeignPtr, unsafeForeignPtrToPtr)
import Foreign.C.Types    (CULong, CUInt)
import System.Glib.GType	(GType, typeInstanceIsA)
@MODULE_IMPORTS@
{# context lib="@CONTEXT_LIB@" prefix="@CONTEXT_PREFIX@" #}

-- The usage of foreignPtrToPtr should be safe as the evaluation will only be
-- forced if the object is used afterwards
--
castTo :: (@ROOTOBJECT@Class obj, @ROOTOBJECT@Class obj') => GType -> String
                                                -> (obj -> obj')
castTo gtype objTypeName obj =
  case to@ROOTOBJECT@ obj of
    gobj\@(@ROOTOBJECT@ objFPtr)
      | typeInstanceIsA ((unsafeForeignPtrToPtr.castForeignPtr) objFPtr) gtype
                  -> unsafeCast@ROOTOBJECT@ gobj
      | otherwise -> error $ "Cannot cast object to " ++ objTypeName

@DECLARATIONS@