On 15 September 2010 00:44, Thomas DuBuisson
The "split" routine in the RandomGen seems to be a sore spot for some people and is perceived to have few users (even as a percentage of RandomGen users). I propose:
1) Making a class "SplittableGen":
class SplittableGen g where split :: g -> (g, g)
2) (re)moving the "split" routine from the RandomGen class.
See ticket 4314 [1] for the patch.
Period of discussion: Till October 8 (3.5 weeks, ending just over 1 week after ICFP)
I support this change. The rationale is that while split is very useful (e.g. in pure lazy code), there are many PRNGs that are not splitable. Thus simply splitting the existing functions into two classes allows many common PRNGs to be instances of the main random gen type class without forcing them to implement bogus split functions. I do not think we need to go as far as Bryan suggests and provide estimates of remaining entropy. If there is demand for tracking entropy then we can do it separately. This change is fairly minimal as it only changes type class names in type signatures, not function names, function parameters or module imports. We should however consider this change in the context of the other proposals for the random class. If however those changes cannot be agreed, this smaller change could go through on its own, IMHO. Duncan