Confused about Random

[Ian Lynagh]

With the following module:

    module Main where

    import Random

    data Foo = Foo StdGen

    main :: IO()
    main = do let rs = randoms (Foo (mkStdGen 39)) :: [Int]
                  rRs =  randomRs (0,9) (Foo (mkStdGen 39)) :: [Int]
              putStrLn $ show $ take 100 rs
              putStrLn $ show $ take 100 rRs

    instance RandomGen Foo where
     genRange _ = (0, 1)
     next (Foo g) = (val `mod` 2, Foo g')
      where (val, g') = random g
     split _ = error "Not implemented"

ghc gives me

[-2147476078,7482,-2147476078,-2147476078,-2147476079,-2147476078,7483,7482,7482,-2147476079,-2147476078,-2147476079,-2147476079,7482,-2147476078,-2147476078,-2147476078,-2147476079,7482,7483,7482,7483,7482,-2147476078,-2147476078,-2147476078,7483,-2147476079,7482,-2147476078,-2147476079,-2147476078,7483,-2147476079,7483,7482,-2147476079,7483,7482,7483,-2147476078,-2147476079,-2147476079,7482,-2147476078,7482,-2147476079,-2147476079,7482,-2147476078,7483,7483,-2147476079,-2147476078,7483,7483,-2147476078,-2147476079,-2147476078,-2147476079,-2147476078,7483,7483,7482,7482,7483,-2147476078,-2147476079,-2147476079,7482,7483,-2147476078,-2147476079,-2147476079,-2147476078,7482,7483,-2147476079,7482,7482,7482,7483,-2147476079,-2147476079,-2147476078,7482,7482,7482,7482,-2147476079,7482,7482,-2147476079,7483,-2147476078,7482,7483,-2147476079,-2147476079,7482]
[1,2,2,1,1,2,1,2,1,1,1,2,2,2,2,1,2,1,1,1,1,2,1,1,1,1,2,1,1,2,1,2,1,2,1,1,2,1,2,2,2,1,2,2,2,1,1,2,1,2,1,2,2,2,1,1,2,1,1,2,1,1,1,2,2,2,1,1,2,2,2,1,1,1,2,2,2,1,2,2,1,2,1,1,1,1,2,1,1,2,2,1,1,1,1,1,2,1,1,2]

The first list doesn't seem to cover the whole spectrum and I was
expecting the second list to be composed over 0s through 9s. Is my
understanding wrong?

nhc complains
    Context for Random.Random needed in left hand pattern at 17:11.
and hugs doesn't seem to know genRange exists. With it commented out it
returns the same as ghc.


Thanks
Ian