Test.QuickCheck.Function

Generation of random shrinkable, showable functions.

To generate random values of type Fun a b, you must have an instance Function a.

See also applyFun, and Fn with GHC >= 7.8.

Create a `Fun` from a function representation and a default value (in case the function is partial).

Extracts the value of a function.

Fn is the pattern equivalent of this function.

prop :: Fun String Integer -> Bool
prop f = applyFun f "banana" == applyFun f "monkey"
      || applyFun f "banana" == applyFun f "elephant"

Alias to applyFun.

Extracts the value of a binary function.

Fn2 is the pattern equivalent of this function.

prop_zipWith :: Fun (Int, Bool) Char -> [Int] -> [Bool] -> Bool
prop_zipWith f xs ys = zipWith (applyFun2 f) xs ys == [ applyFun2 f x y | (x, y) <- zip xs ys]

Extracts the value of a ternary function. Fn3 is the pattern equivalent of this function.

The type of possibly partial concrete functions

The class Function a is used for random generation of showable functions of type a -> b.

There is a default implementation for function, which you can use if your type has structural equality. Otherwise, you can normally use functionMap or functionShow.

The basic building block for Function instances. Provides a Function instance by mapping to and from a type that already has a Function instance.

Provides a Function instance for types with Show and Read.

Provides a Function instance for types with Integral.

Provides a Function instance for types with RealFrac.

Provides a Function instance for types with Bounded and Enum. Use only for small types (i.e. not integers): creates the list [minBound..maxBound]!

Provides a Function instance for small finite types.

Provides a Function instance for types isomorphic to Void.

An actual Function Void instance is defined in quickcheck-instances.

A modifier for testing functions.

prop :: Fun String Integer -> Bool
prop (Fn f) = f "banana" == f "monkey"
           || f "banana" == f "elephant"

A modifier for testing binary functions.

prop_zipWith :: Fun (Int, Bool) Char -> [Int] -> [Bool] -> Bool
prop_zipWith (Fn2 f) xs ys = zipWith f xs ys == [ f x y | (x, y) <- zip xs ys]

A modifier for testing ternary functions.