Re: Instances for data types

Sven Panne wrote:

Playing around with System.Posix.Terminal, I realized that there are no Read, Show, Eq, Enum, ... instances for the data types defined there (TerminalState, TerminalMode, ...). This is not a very difficult problem to solve in one's own program, but it's not very handy, either.

Two other cases where I have to roll my own Typeable instance are Data.FiniteMap.FiniteMap and HaXml's Element type (and friends) This is all very well but will cause problems if someone else imports one of my packages and another one which defines conflicting instances of Typeable. Or if later the standard libraries or some library I use change to implement their own Typeable instance.