27 Nov
2009
27 Nov
'09
5:44 a.m.
I know that 2 is something of the type Integral, however what does this differ from Int? The same question goes for Fractional and Floating, what exactly is their commonality and what exactly is their difference?
Numeric literals are a special case. To make it possible to write "2" and mean it as an Int or an Integer (or any other numeric type), 2 is defined to *really* mean (fromIntegral 2). fromIntegral is a function that takes an Integral value (such as 2), and converts it to a type of your choice, so long as it's a member of the Num class.
Ahem. 2 is defined to really mean (fromInteger 2), not "fromIntegral". And "fromInteger" takes an *Integer* value.