It seems like a reasonable and not-too-painful solution, thanks!
Concerning Haskell typesystem, I know it to be beautiful, but also kind of
complex. One of the great Haskell assets is genericity, but this complexity
sometimes encumbers this genericity.
But still, Haskell is -- in terms of flexibility -- way before other
languages which pretend to be generic.
2010/4/18 Sebastian Fischer
On Apr 18, 2010, at 11:01 AM, Limestraël wrote:
It's strange I can't declare a generic instance for Binary types... I
thought I was trying to do something quite common in Haskell.
A common workaround is to define a newtype like this
newtype GenericBinary a = GB { fromGB :: a }
and an instance like this
instance Binary a => Binarizable (GenericBinary a) a where toBinary = fromGB
which only needs FlexibleInstances enabled.
You can then 'tag' Binary types for which you want to use the generic default instance above with the GB newtype constructor. Whether this is less of a pain than implementing a Binarizable instance for each Binary type is a different question..
Sebastian
-- Underestimating the novelty of the future is a time-honored tradition. (D.G.)