23 Apr
2009
23 Apr
'09
10:40 a.m.
On 23 Apr 2009, at 16:25, Daniel Carrera wrote:
Thomas Davie wrote:
It looks like (/) is happy with Num but doesn't like Int. This surprises me. I would have thought that Fractional is a kind of Num and Int is a kind of Fractional Int isn't a Fractional because it can't represent fractional numbers.
Sure, but any integer is trivially also a fraction, so I would think that it would be an acceptable input for (/). On the other hand, if it is at all possible for a Num to contain something that cannot be converted to a fraction, then a Num should not be a valid input for (/).
The problem here is that (/) also *outputs* that type – if you can't represent a fraction, how do you give the result of 1/4? Bob