Paul Johnson wrote:
Dominic Steinitz wrote:
Unfortunately for your purpose you would need:
*generate* :: (RandomGen g) => Int http://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Int.html#t%3... -> g -> Gen http://www.haskell.org/ghc/docs/latest/html/libraries/QuickCheck/Test-QuickC... a -> a
Thanks - rather what I thought. This seems to do the trick using a state monad but it doesn't look pretty. import Test.QuickCheck import Control.Monad.State data Baz = Baz String Int deriving (Eq, Show) g :: MonadState Int m => m (Gen Int) g = do x <- get put (x + 1) return (return x) f :: MonadState Int m => Int -> m (Gen [Baz]) f 0 = return (return []) f n = do x <- g xs <- f (n - 1) let z = do u <- x us <- xs v <- arbitrary return ((Baz ("t" ++ (show u)) v):us) return z *Main> let (q,p) = runState (f 10) 1 in sample q [Baz "t1" (-1),Baz "t2" 0,Baz "t3" 0,Baz "t4" (-1),Baz "t5" 1,Baz "t6" 1,Baz "t7" 1,Baz "t8" 1,Baz "t9" 1,Baz "t10" 1] [Baz "t1" 0,Baz "t2" 2,Baz "t3" (-2),Baz "t4" (-2),Baz "t5" (-1),Baz "t6" 0,Baz "t7" 1,Baz "t8" 2,Baz "t9" (-2),Baz "t10" (-2)] This gives me what I wanted: distinct (and in this case predictable) names and random values.
Take a look at SmallCheck. It might be more suited to your requirement anyway.
I will do so now. Thanks, Dominic.