On Tue, 4 Nov 2014, Simon Peyton Jones wrote:
pattern P :: forall tvs. (match-provided ; match-required) => tau
The "; match-required" part is optional, and the "match-provided" part might be
empty. So P1 and P2 would look like this:
pattern P1 :: forall a. (; Num a) => b -> (a,b)
pattern P2 :: forall a. (; Num a, Ord a) => a -> a
Doesn't the ';' look a bit like something that could be incidentially
introduced by some layout-aware syntax rule? Wouldn't, e.g., '|' be more
explicit as a separator?
example:
pattern P :: forall tvs. (Eq b | Num a, Eq a) => b -> T a
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