[Haskell-beginners] Quickcheck Preconditions

Jonas Almström Duregård jonas.duregard at chalmers.se
Wed May 25 21:27:52 CEST 2011


abs $ (n `mod` (y - x)) + x

Provided y > x >= 0.

/J

On 25 May 2011 18:13, Guy <guytsalmaves-h at yahoo.com> wrote:

> Simply stating that I need an integer between X and Y
>
>
> On 25/05/2011 18:42, Jonas Almström Duregård wrote:
>
>> Not sure what you mean by "specifying bounds for quickcheck".
>>
>>
>> 2011/5/25 Guy<guytsalmaves-h at yahoo.com>:
>>
>>> Thanks, mod is a neat trick for applying the size. Is there a simple way
>>> of specifying bounds for quickcheck, or would I have to write a custom
>>> generator to do that?
>>>
>>>
>>>  ________________________________
>>>> From: Jonas Almström Duregård<jonas.duregard at chalmers.se>
>>>> Sent: Wednesday, 25 May 2011, 14:09
>>>> Subject: Re: [Haskell-beginners] Quickcheck Preconditions
>>>>
>>>>
>>>> You can write your own generators and use the forall function. Or for
>>>> these simple examples you can just test on wrappers:
>>>>
>>>>
>>>> testFoo :: (a,a,a,[a]) ->  IO Bool
>>>> testFoo (a1,a2,a3,as) = foo (a1:a2:a3:as)
>>>>
>>>>
>>>> testBar :: (a,[a]) ->  Int ->  IO ()
>>>> testBar (x,xs) n = bar xs' (n `mod` length xs') where xs' = x:xs
>>>>
>>>>
>>>> /J
>>>>
>>>
>
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