deque-blog’s gists

deque-blog / rapid_check_testable_induction.hs

Last active February 2, 2017 22:06

	instance
	(Show a, Arbitrary a,
	Testable testable)
	=> Testable (a -> testable)
	where
	property f = forAll arbitrary f

	forAll :: (Show a, Testable testable) => Gen a -> (a -> testable) -> Property
	forAll = undefined

deque-blog / rapid_check_testable.hs

Created January 31, 2017 19:46

	class Testable a where
	property :: a -> Property

deque-blog / rapid_check_testable_induction_goal.hs

Last active February 2, 2017 22:04

	instance
	(Show a, Arbitrary a, -- Given a type `a` supporting random generation
	Testable testable) -- And an already existing testable function
	=> Testable (a -> testable) -- The function (a -> testable) is also testable
	where
	property = undefined -- With the provided implementation

deque-blog / rapid_check_forall.hs

Last active February 2, 2017 12:06

	forAll :: (Show a, Testable testable) => Gen a -> (a -> testable) -> Property
	forAll argGen prop =
	Property $ Gen $ \rand -> -- Create a new property that will
	let (rand1, rand2) = split rand -- Split the generator in two
	arg = runGen argGen rand1 -- Use the first generator to produce an arg
	subProp = property (prop arg) -- Use the `a` to access the sub-property
	result = runProp subProp rand2 -- Use the second generator to run it
	in overFailure result $ \failure -> -- Enrich the counter-example with `arg`
	failure { counterExample = show arg : counterExample failure }

deque-blog / rapid_check_rapidCheck.hs

Last active February 2, 2017 12:12

	rapidCheck :: Testable prop => prop -> IO Result
	rapidCheck = rapidCheckWith 100

	rapidCheckWith :: Testable prop => Int -> prop -> IO Result
	rapidCheckWith attemptNb prop = do
	seed <- randomIO
	return $ rapidCheckImpl attemptNb seed prop

deque-blog / bench_open_recursion.cpp

Last active February 1, 2017 21:14

	#include <unordered_map>
	#include <vector>

	//------------------------------------------------------------------------

	long long bst_count_classic(int n)
	{
	if (n <= 1) return 1;

	std::vector<long long> memo(n+1, 0);

deque-blog / rapid_check_result_utils.hs

Created February 1, 2017 22:20

	overFailure :: Result -> (Result -> Result) -> Result
	overFailure Success _ = Success
	overFailure failure f = f failure

deque-blog / rapid_check_property_utils.hs

Created February 1, 2017 22:25

	runProp :: Property -> StdGen -> Result
	runProp prop rand = runGen (getGen prop) rand

deque-blog / rapid_check_rapidCheckImpl.hs

Created February 2, 2017 12:12

	rapidCheckImpl :: Testable prop => Int -> Int -> prop -> Result
	rapidCheckImpl attemptNb startSeed prop = runAll (property prop)
	where
	runAll prop = foldMap (runOne prop) [startSeed .. startSeed + attemptNb - 1]
	runOne prop seed =
	let result = runProp prop (mkStdGen seed)
	in overFailure result $ \failure -> failure { seed = seed }

deque-blog / rapid_check_integer_arbitrary.hs

Last active February 2, 2017 18:10

	instance Arbitrary Integer where
	arbitrary = Gen $ \rand ->
	fromIntegral (fst (next rand))