Finally, I found a solution in haskell-user list http://www.mail-archive.com/glasgow-haskell-users@haskell.org/msg01693.html Thanks, Janna -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.haskell.org/pipermail/glasgow-haskell-bugs/attachments/20010123/4e3e3e6b/attachment.htm