[Haskell-cafe] Other instances of Integral
Miguel Mitrofanov
miguelimo38 at yandex.ru
Fri Nov 27 08:17:13 EST 2009
Tsunkiet Man wrote:
> Hello,
>
> I would like to ask wheter there are other instances of the class
> Integral?
Lots of them. You can define a few of them yourself, you know.
> And I would like to ask what the difference is between the
> following functions: SomeFunctionA :: (Integral a) => a -> a,
Perfectly correct.
> SomeFunctionB (Integer a) => a -> a, SomeFunctionC (Int a) => a -> a.
Both incorrect.
Integral is a class, but Integer and Int are types.
> What I do know is, that the Int can have underflow and overflows,
> however I don't actually see the difference (and I can't really find a
> difference on Google as it gives me results that aren't really relevant
> to my question) between prefering to use an Integral a when I've already
> got an Integer.
Sorry, didn't understand your question.
> (Assuming I didn't missed the definiton of a Integral,
> which has by definition (I looked it up on Google:
> http://www.zvon.org/other/haskell/Outputprelude/Integral_c.html) has two
> instances)
No. It makes no sense to say "by definition ... has that number of instances". Instances of class are not included in it's definition and could be defined separately.
> Can someone explain to me what kind of advantages and disadvantages I
> would get when substituting SomeFunctionB for someFunctionA?
Working program would certainly be an advantage.
> Thank you for your help!
>
>
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