I hope that typeRepKey is no longer in the IO monad (for the simple reason to
teach me that the key can change between session). This forced me to use
unsafePerformIO to make a typeable boxed type of instances of Ord an
instance of Ord (to put it in a Map). Or did I miss something and I can do
better anyhow?
e.g.:
class (Ord s, Typeable s) => Selector s
data GenSelector = forall s . Selector s => GS s
instance Ord GenSelector where
compare (GS a) (GS b) = if typeOf a == typeOf b then
compare (fromJust (cast a)) b
else compare (unsafePerformIO $ typeRepKey $ typeOf a)
(unsafePerformIO $ typeRepKey $ typeOf b)
Jürgen Nicklisch
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