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POHow to print generated result from arbitrary?
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copied!<p>quickCheckResult only accept <code>something -> Bool</code>, then i mimic some example, pass </p> <pre><code>[Colour] -> Bool </code></pre> <p>what is function of the bracket of [Colour]? why not <code>Colour -> Bool</code>? How to pass Arbitrary instance to quickCheckResult?</p> <pre><code>data Colour = Green | Blue instance Arbitrary Colour where arbitrary = oneof [return Green, return Blue] main = quickCheckResult ((\s -> s == s) :: [Colour] -> Bool) </code></pre> <p>[Updated] My goal is the following can run</p> <pre><code>import Test.QuickCheck.Function import Test.QuickCheck.Gen import Test.QuickCheck import Test.QuickCheck.Function import Test.QuickCheck.Arbitrary import Test.QuickCheck.Property import Test.QuickCheck.Test prop1 f g x = (g.f) x == (f.g) x where types = [f, g] :: [Int->Int] instance CoArbitrary ex where coarbitrary f g = prop1 (variant 0 f) (variant 0 g) main = quickCheck prop1 test5.hs:11:10: Illegal instance declaration for `CoArbitrary ex' (All instance types must be of the form (T a1 ... an) where a1 ... an are *distinct type variables*, and each type variable appears at most once in the instance head. Use -XFlexibleInstances if you want to disable this.) In the instance declaration for `CoArbitrary ex' </code></pre> <p>3.How to use QuickCheck.Function (Updated)</p> <pre><code>prop :: Fun Fun Integer -> Bool let prop (Fun _ f) (Fun _ g) = (g.f) x == (f.g) x quickCheck prop </code></pre> <p>parse error (possibly incorrect indentation)</p>

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