gistfile1.rs

trait Rand<Distribution> {
    type Stream: RandStream<T>;
    fn rand(dist: Distribution) -> Stream;
}

trait RandStream<T> {
    fn next<R: Rng>(&self, rng: &mut R) -> T;
}

impl Rand<Range<u32, u32>> for u32 {
    type Stream = SomePreprocessedDistribution;
    fn rand(dist: Range<u32, u32>) -> Stream {
        SomePreprocessedDistribution::preprocess(dist)
    }
}

impl RandStream<u32> for SomePreprocessedDistribution {
    fn next<R: Rng>(&self, rng: &mut R) -> u32 {
        // do the sampling
    }
}