Merge pull request #48 from purescript/repeatable

Fix 'repeatable'

Author: paf31

docs/Test/QuickCheck.md

@@ -73,9 +73,9 @@ Testable properties can be passed to the `quickCheck` function.
 
 ##### Instances
 ``` purescript
-instance testableResult :: Testable Result
-instance testableBoolean :: Testable Boolean
-instance testableFunction :: (Arbitrary t, Testable prop) => Testable (t -> prop)
+Testable Result
+Testable Boolean
+(Arbitrary t, Testable prop) => Testable (t -> prop)
 ```
 
 #### `Result`
@@ -90,8 +90,8 @@ The result of a test: success or failure (with an error message).
 
 ##### Instances
 ``` purescript
-instance testableResult :: Testable Result
-instance showResult :: Show Result
+Testable Result
+Show Result
 ```
 
 #### `(<?>)`
@@ -113,7 +113,7 @@ test x = myProperty x <?> ("myProperty did not hold for " <> show x)
 #### `(===)`
 
 ``` purescript
-(===) :: forall a b. (Eq a, Show a) => a -> a -> Result
+(===) :: forall a. (Eq a, Show a) => a -> a -> Result
 ```
 
 _left-associative / precedence -1_
@@ -123,7 +123,7 @@ Self-documenting equality assertion
 #### `(/==)`
 
 ``` purescript
-(/==) :: forall a b. (Eq a, Show a) => a -> a -> Result
+(/==) :: forall a. (Eq a, Show a) => a -> a -> Result
 ```
 
 _left-associative / precedence -1_

docs/Test/QuickCheck/Arbitrary.md

@@ -16,18 +16,21 @@ module can be used to construct random generators.
 
 ##### Instances
 ``` purescript
-instance arbBoolean :: Arbitrary Boolean
-instance arbNumber :: Arbitrary Number
-instance arbInt :: Arbitrary Int
-instance arbString :: Arbitrary String
-instance arbChar :: Arbitrary Char
-instance arbUnit :: Arbitrary Unit
-instance arbOrdering :: Arbitrary Ordering
-instance arbArray :: (Arbitrary a) => Arbitrary (Array a)
-instance arbFunction :: (Coarbitrary a, Arbitrary b) => Arbitrary (a -> b)
-instance arbTuple :: (Arbitrary a, Arbitrary b) => Arbitrary (Tuple a b)
-instance arbMaybe :: (Arbitrary a) => Arbitrary (Maybe a)
-instance arbEither :: (Arbitrary a, Arbitrary b) => Arbitrary (Either a b)
+Arbitrary Boolean
+Arbitrary Number
+Arbitrary Int
+Arbitrary String
+Arbitrary Char
+Arbitrary Unit
+Arbitrary Ordering
+(Arbitrary a) => Arbitrary (Array a)
+(Coarbitrary a, Arbitrary b) => Arbitrary (a -> b)
+(Arbitrary a, Arbitrary b) => Arbitrary (Tuple a b)
+(Arbitrary a) => Arbitrary (Maybe a)
+(Arbitrary a, Arbitrary b) => Arbitrary (Either a b)
+(Arbitrary a) => Arbitrary (List a)
+(Arbitrary a) => Arbitrary (Identity a)
+(Arbitrary a) => Arbitrary (Lazy a)
 ```
 
 #### `Coarbitrary`
@@ -48,18 +51,21 @@ is the role of the `coarbitrary` function.
 
 ##### Instances
 ``` purescript
-instance coarbBoolean :: Coarbitrary Boolean
-instance coarbNumber :: Coarbitrary Number
-instance coarbInt :: Coarbitrary Int
-instance coarbString :: Coarbitrary String
-instance coarbChar :: Coarbitrary Char
-instance coarbUnit :: Coarbitrary Unit
-instance coarbOrdering :: Coarbitrary Ordering
-instance coarbArray :: (Coarbitrary a) => Coarbitrary (Array a)
-instance coarbFunction :: (Arbitrary a, Coarbitrary b) => Coarbitrary (a -> b)
-instance coarbTuple :: (Coarbitrary a, Coarbitrary b) => Coarbitrary (Tuple a b)
-instance coarbMaybe :: (Coarbitrary a) => Coarbitrary (Maybe a)
-instance coarbEither :: (Coarbitrary a, Coarbitrary b) => Coarbitrary (Either a b)
+Coarbitrary Boolean
+Coarbitrary Number
+Coarbitrary Int
+Coarbitrary String
+Coarbitrary Char
+Coarbitrary Unit
+Coarbitrary Ordering
+(Coarbitrary a) => Coarbitrary (Array a)
+(Arbitrary a, Coarbitrary b) => Coarbitrary (a -> b)
+(Coarbitrary a, Coarbitrary b) => Coarbitrary (Tuple a b)
+(Coarbitrary a) => Coarbitrary (Maybe a)
+(Coarbitrary a, Coarbitrary b) => Coarbitrary (Either a b)
+(Coarbitrary a) => Coarbitrary (List a)
+(Coarbitrary a) => Coarbitrary (Identity a)
+(Coarbitrary a) => Coarbitrary (Lazy a)
 ```
 
 

docs/Test/QuickCheck/Data/AlphaNumString.md

@@ -12,8 +12,8 @@ alphanumeric strings.
 
 ##### Instances
 ``` purescript
-instance arbAlphaNumString :: Arbitrary AlphaNumString
-instance coarbAlphaNumString :: Coarbitrary AlphaNumString
+Arbitrary AlphaNumString
+Coarbitrary AlphaNumString
 ```
 
 #### `runAlphaNumString`

docs/Test/QuickCheck/Data/ApproxNumber.md

@@ -12,15 +12,15 @@ for precision erros when comparing.
 
 ##### Instances
 ``` purescript
-instance arbitraryApproxNumber :: Arbitrary ApproxNumber
-instance coarbitraryApproxNumber :: Coarbitrary ApproxNumber
-instance eqApproxNumber :: Eq ApproxNumber
-instance ordApproxNumber :: Ord ApproxNumber
-instance semiringApproxNumber :: Semiring ApproxNumber
-instance moduloSemiringApproxNumber :: ModuloSemiring ApproxNumber
-instance ringApproxNumber :: Ring ApproxNumber
-instance divisionRingApproxNumber :: DivisionRing ApproxNumber
-instance numApproxNumber :: Num ApproxNumber
+Arbitrary ApproxNumber
+Coarbitrary ApproxNumber
+Eq ApproxNumber
+Ord ApproxNumber
+Semiring ApproxNumber
+ModuloSemiring ApproxNumber
+Ring ApproxNumber
+DivisionRing ApproxNumber
+Num ApproxNumber
 ```
 
 #### `(=~=)`

docs/Test/QuickCheck/Gen.md

@@ -166,7 +166,7 @@ Run a random generator, keeping only the randomly-generated result
 #### `sample`
 
 ``` purescript
-sample :: forall r a. Seed -> Size -> Gen a -> Array a
+sample :: forall a. Seed -> Size -> Gen a -> Array a
 ```
 
 Sample a random generator

docs/Test/QuickCheck/LCG.md

@@ -27,6 +27,14 @@ It is equal to 2^31 - 1, a Mersenne prime. It is useful for this value to
 be prime, because then the requirement of the initial seed being coprime
 to the modulus is satisfied when the seed is between 1 and lcgN - 1.
 
+#### `lcgPerturb`
+
+``` purescript
+lcgPerturb :: Number -> Seed -> Seed
+```
+
+Perturb a seed value
+
 #### `lcgNext`
 
 ``` purescript
@@ -55,8 +63,8 @@ seed for the generator.
 
 ##### Instances
 ``` purescript
-instance showSeed :: Show Seed
-instance eqSeed :: Eq Seed
+Show Seed
+Eq Seed
 ```
 
 #### `mkSeed`

src/Test/QuickCheck/Gen.purs

@@ -34,11 +34,13 @@ import Control.Monad.Eff.Random (RANDOM())
 import Control.Monad.State (State(), runState, evalState)
 import Control.Monad.State.Class (state, modify)
 import Control.Monad.Rec.Class (MonadRec, tailRecM)
+import Math ((%))
 import Data.Array ((!!), length)
 import Data.Tuple (Tuple(..))
 import Data.Foldable (fold)
-import Data.Int (toNumber)
+import Data.Int (toNumber, fromNumber)
 import Data.Maybe (fromMaybe)
+import Data.Maybe.Unsafe as U
 import Data.Monoid.Additive (Additive(..), runAdditive)
 import Data.Tuple (Tuple(..), fst, snd)
 import Data.Either (Either(..))
@@ -60,7 +62,7 @@ type Gen a = State GenState a
 
 -- | Create a random generator for a function type.
 repeatable :: forall a b. (a -> Gen b) -> Gen (a -> b)
-repeatable f = state $ \s -> Tuple (\a -> fst (runGen (f a) s)) s
+repeatable f = state $ \s -> Tuple (\a -> fst (runGen (f a) s)) (s { newSeed = lcgNext s.newSeed })
 
 -- | Create a random generator which uses the generator state explicitly.
 stateful :: forall a. (GenState -> Gen a) -> Gen a
@@ -187,7 +189,5 @@ foreign import float32ToInt32 :: Number -> Int
 -- | Perturb a random generator by modifying the current seed
 perturbGen :: forall a. Number -> Gen a -> Gen a
 perturbGen n gen = do
-  modify \s -> s { newSeed = perturb s.newSeed }
+  modify \s -> s { newSeed = lcgPerturb (toNumber (float32ToInt32 n)) s.newSeed }
   gen
-  where
-  perturb oldSeed = mkSeed (runSeed (lcgNext (mkSeed (float32ToInt32 n))) + runSeed oldSeed)

src/Test/QuickCheck/LCG.purs

@@ -6,6 +6,7 @@ module Test.QuickCheck.LCG
   , lcgC
   , lcgN
   , lcgNext
+  , lcgPerturb
   , randomSeed
   ) where
 
@@ -32,11 +33,15 @@ lcgC = 0
 lcgN :: Int
 lcgN = 2147483647
 
+-- | Perturb a seed value
+lcgPerturb :: Number -> Seed -> Seed
+lcgPerturb d = Seed <<< go <<< runSeed
+  where
+  go n = U.fromJust $ fromNumber $ (toNumber lcgM * toNumber n + d) % toNumber lcgN
+
 -- | Step the linear congruential generator
 lcgNext :: Seed -> Seed
-lcgNext = Seed <<< go <<< runSeed
-  where
-  go n = U.fromJust $ fromNumber $ (toNumber lcgM * toNumber n + toNumber lcgC) % toNumber lcgN
+lcgNext = lcgPerturb (toNumber lcgC)
 
 -- | Create a random seed
 randomSeed :: forall e. Eff (random :: RANDOM | e) Seed