If I for some data type wants to derive, in this case Data and
Typeable for use with syb code, but the problem is the same regardless
what I want to derive.
data family Something
data Tree = Leaf Something | Fork Something Tree Tree
deriving (Data, Typeable)
The problem is I want to derive a class for a data type that depends
on some non instantiated data type.
I can of course rewrite Tree as:
data (Data a) => Tree a = Leaf a | Fork a Tree Tree
deriving (Data, Typeable)
but then data family Something is redundant, I want to think of
Something as a not yet instantiated abstract data type
Is there anyway to express that either the instance of Something used
in Tree should be a member of Data, or even better
any instance of Something should be a member of Data or maybe even
better that every instance should derive data.
data family Something
deriving Data
//Tuve Nordius
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