slemi wrote:
oh well thats pretty straight-forward:)
the next thing i don't understand is how ghci turns 1 into (Scalar 1). 1 == (Scalar 1) returns True, which is logical in a way (NOT), but if i change the type definition to data Matrix a = Matr {unMatr :: [[a]]} | Lol a | Scalar a then 1 == (Scalar 1) still returns True, but 1 == (Lol 1) returns False, no matter in what order I put them in the definition... o.O
Numeric literals in Haskell are overloaded. 1 really means fromInteger 1. The function fromInteger is defined by instances of Num. This is why you can use a numeric literal wherever your program expects a Double, Int, Integer, and so on. This includes your own type. You have probably defined fromInteger = Scalar for your type. Cheers, Jochem -- Jochem Berndsen | jochem@functor.nl | jochem@牛在田里.com