[Haskell-cafe] Wondering if this could be done.
schlepptop at henning-thielemann.de
Sat Dec 4 11:38:45 CET 2010
> On 22 November 2010 07:48, Magicloud Magiclouds
> <magicloud.magiclouds at gmail.com <mailto:magicloud.magiclouds at gmail.com>>
> 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?
(*) and (+) are in separate type classes in Numeric-Prelude.
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