[Haskell-cafe] Other instances of Integral

[Tsunkiet Man]

2009/11/27 Miguel Mitrofanov <miguelimo38 at yandex.ru>

>
>
> 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.

 Yes, I knew that =).


>
> 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.

 Was not really a 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.

 Ah I see!


>
> 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.



> What if it both works? Should I take the "highest level"?
>
 Thank you for your help!
>>
>>
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>>
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>>
> This is actually all related to my homework problem which I can't seem to
get a usefull answer out. Cause it tells me that a definition with Integrals
would be much more general. It can support other instances of the class
Integral. And then it asks me what the difference the definition has,
actually it has none. Because I only use functions in de Prelude that are
defined for Integrals.

Correct me if I'm wrong with this =).

I don't really understand how I should answer this homework question as it
makes no sense in my opinion give me the answer and then asking me the
question xD.

Thanks for your quick response!
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