[Haskell-cafe] classes question

[Paul Tokarev]

Thanks, that works. But how sould I change my class definition, so that it
works without (2::Int), but just with 2?


Ross Mellgren wrote:
> 
> You did not specify what type of number it is -- in Haskell numeric  
> constants like "1" are actually typed as forall a. Num a -- that is,  
> can be any type of Num.
> 
> Try: plus (2::Int) 3
> 
> -Ross
> 
> On Nov 9, 2009, at 1:44 PM, Paul Tokarev wrote:
> 
>>
>> Hi.
>>
>> I am using Hugs 98
>> I have that piece of code:
>>
>> class PlusTimes a where
>>   plus :: a -> a -> a
>>
>> instance PlusTimes Int where
>>   plus x y = x + y
>>
>> when I run : "plus 2 3" I get this error:
>> ERROR - Unresolved overloading
>> *** Type       : (Num a, PlusTimes a) => a
>> *** Expression : plus 2 3
>>
>> What am I doing wrong?
>> Thanks.
>>
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