8 Feb
2006
8 Feb
'06
12:48 p.m.
| > b) A pattern type signature may bring into scope a skolem bound | > in the same pattern: | > data T where | > MkT :: a -> (a->Int) -> T | > f (MkT (x::a) f) = ... | > | > The skolem bound by MkT can be bound *only* in the patterns that | > are the arguments to MkT (i.e. pretty much right away). | | I see -- my scheme was overly simple. But this too feels unsatisfactory. | What if we want to give signatures for both arguments? Will the a's | be the same? Yes f (MkT (x::a) (f::a->Int)) = ... You can imagine that either (a) both bind 'a' to the skolem, but must do consistently; or (b) that (x::a) binds 'a', and (f::a->Int) is a bound occurrence. It doesn't matter which you choose, I think. Simon