[Haskell-cafe] Polymorphic (typeclass) values in a list?
Kalman Noel
kalman.noel at bluebottle.com
Fri Oct 19 13:58:42 EDT 2007
Jules Bean wrote:
> This looks very very much clearer in GADT syntax, since in GADT syntax
> you always give constructors explicit types:
>
> type ExistsNumber where
> Number :: forall a . Num a => ExistsNumber a
The questions in response to my post have been answered already; I'd like to
mention, though, the two typos in your example, which should read instead:
data ExistsNumber where
Number :: forall a. Num a => a -> ExistsNumber
Kalman
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