Hello,
Please, who knows what are the "deriving possibilites" in Haskell-1.4?
Suppose we define in our program the classes D1..D6, the data
constructor F, and the instances
instance C1 a => D1 (F a) where ...
...
instance C6 a => D6 (F a) where ...
Now, for data G a = G (F a)
we are is going to "copy" D1-D4 instances to G a by "deriving"
(using the natural isomorphism F a <--> G a)
and define D5,D6 in another way.
Could we set data G a = G (F a) deriving(D1,D2,D3,D4)
or something instead of this?
------------------
Sergey Mechveliani
[EMAIL PROTECTED]
