Hi John,
NB
the essence what I am trying to do is to define a proxy class Foo for
class Ba1 I would have thought that something as simple as the
following would have worked ??
class Ba1 a where
dosomething :: a -> IO ()
ba1 :: Ba1 a => a -> IO ()
ba1 x = dosomething x
instance Ba1 Int w
m remains.
--
Robin Bate Boerop
On 22-Apr-06, at 2:01 PM, Gerrit van den Geest wrote:
Robin,
The following does NOT work, because of a duplicate instance
declaration for A:
class A a
class B1 b1
class B2 b2
instance B1 x => A x
instance B2 x => A x -- duplicate instance, won't c
m remains.
--
Robin Bate Boerop
On 22-Apr-06, at 2:01 PM, Gerrit van den Geest wrote:
Robin,
The following does NOT work, because of a duplicate instance
declaration for A:
class A a
class B1 b1
class B2 b2
instance B1 x => A x
instance B2 x => A x -- duplicate instance, won't c
Robin,
The following does NOT work, because of a duplicate instance declaration
for A:
class A a
class B1 b1
class B2 b2
instance B1 x => A x
instance B2 x => A x -- duplicate instance, won't compile
data T = T
instance B1 T
Yes, this doesn't work and I think there is no GHC extension that
