[Haskell-cafe] Wondering if this could be done.

Hi, For example, I have a data A defined. Then I want to add (+) and (-) operators to it, as a sugar (compared to addA/minusA). But * or other stuff defined in class Num is meanless to A. So I just do: (+) :: A -> A -> A (+) a b = A (elem1 a + elem1 b) (elem2 a + elem2 b) -- I got errors here, for the (+) is ambiguous. So, just wondering, does this way work in Haskell? -- 竹密岂妨流水过 山高哪阻野云飞