On 2010-11-01 19:18 +0100, Jacek Generowicz wrote:
I'm toying with generating random objects (for example tuples) and started wondering what pearls of wisdom Cafe might have on the matter. Two obvious points (relating to my toy code, shown below) are
1) The meaning of the limits required by randomR is not obvious for types such as tuples (you could come up with some definition, but it wouldn't be unique: how would you allow for different ones?[*]; you might decide that having such limits is nonsensical and not want to provide a randomR: would you then leave it undefinded?).
Indeed, the Random class has a fairly narrow "everything fits on the real line" view of the world: not only is the talk about closed intervals ambiguous in general, but so is the talk about uniform distributions on those intervals. That being said, there is an Ord instance for tuples (a lexicographic ordering) and for this case I think it would make the most sense to use that: select an element from the set { x : lo <= x <= hi } -- Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)