On 5 May 2010 11:38, Tim Docker <[email protected]> wrote: > On 5 May 2010 09:01, Ozgur Akgun <[email protected]> wrote: > > your quick check property (in a different way of writing) is > > the following: > > > > prop_1 :: Maybe Double -> Bool > > prop_1 v = v == v > > I think you misunderstood me. The property was fabricated just for > the example. >
OK that's possible :) > > My question was why, when I generate random values for (Maybe t, Maybe > t) using the Arbitrary type class, do I always see two Nothing values > or two Just values, and never one of each? > > Let me try to understand you then. What happens when you run the following command in ghci? sample (arbitrary :: Gen (Maybe Int, Maybe Int) ) Do you still always get (Just _, Just _) or (Nothing, Nothing) pairs, or do you also get some (Nothing, Just _) or (Just _, Nothing) pairs? Ozgur
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