[Haskell-cafe] Quick Question for QuickCheck2

[John Millikin]

Define a custom element generator, which has characters with your
desired values:

myRange :: Gen Char
myRange = elements (['A'..'Z'] ++ ['a' .. 'z'] ++ " ~!@#$%^&*()")

You can use "forAll" to run tests with a specific generator:

forAll myRange $ \c -> chr (ord c) == c

On Mon, Aug 30, 2010 at 08:12, Sebastian Höhn
<sebastian.hoehn at googlemail.com> wrote:
> Hello,
>
> perhaps I am just blind or is it a difficult issue: I would like to
> generate Char values in a given Range for QuickCheck2. There is this
> simple example from the haskell book:
>
> instance Arbitrary Char where
>   arbitrary = elements (['A'..'Z'] ++ ['a' .. 'z'] ++ " ~!@#$%^&*()")
>
> This does not work in QuickCheck2 since the instance is already
> defined. How do I achieve this behaviour in QC2?
>
> Thanks for helping.
>
> Sebastian
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