Is your feature request related to a problem? Please describe.
It is difficult to use quasiquotations that are type safe and can be reused with different types.
f :: (IsReferenceType a, Coercible a) => a -> IO a
f obj = [java| $obj |]
The above code is rejected because at compile time, inline-java doesn't know which Java type to give to $obj.
We can do casts instead:
f :: (IsReferenceType a, Coercible a) => a -> IO a
f (coerce -> JObject obj) = unsafeUncoerce . JObject <$> [java| $obj |]
which can fail at runtime if the user gets the types wrong.
Describe the solution you'd like
Ideally, we would have in Java code like
public <A> A f (A $obj) { return $obj; }and our initial definition would be accepted
f :: (IsReferenceType a, Coercible a) => a -> IO a
f obj = [java| $obj |]
The code generated by inline-java would be responsible for making the appropriate casts.
There is some room to decide where type variables are allowed in a type. Here's an example where the type variable appears nested within a type.
f :: (IsReferenceType a, Coercible a) => a -> IO (J ('Iface "java.util.List" <> '[ Ty a ]))
f _ = [java| new ArrayList<A>() |]
And we also would have to consider if/how to deal with bounded type parameters.
Is your feature request related to a problem? Please describe.
It is difficult to use quasiquotations that are type safe and can be reused with different types.
The above code is rejected because at compile time, inline-java doesn't know which Java type to give to
$obj.We can do casts instead:
which can fail at runtime if the user gets the types wrong.
Describe the solution you'd like
Ideally, we would have in Java code like
and our initial definition would be accepted
The code generated by inline-java would be responsible for making the appropriate casts.
There is some room to decide where type variables are allowed in a type. Here's an example where the type variable appears nested within a type.
And we also would have to consider if/how to deal with bounded type parameters.