1module Spec.Range
2  ( symmetric
3  , bounded
4  , singleton
5  , uniformRangeWithin
6  , uniformRangeWithinExcludedF
7  , uniformRangeWithinExcludedD
8  ) where
9
10import System.Random.Internal
11import System.Random.Stateful
12import Data.Proxy
13
14symmetric :: (RandomGen g, UniformRange a, Eq a) => Proxy a -> g -> (a, a) -> Bool
15symmetric _ g (l, r) = fst (uniformR (l, r) g) == fst (uniformR (r, l) g)
16
17bounded :: (RandomGen g, UniformRange a, Ord a) => Proxy a -> g -> (a, a) -> Bool
18bounded _ g (l, r) = bottom <= result && result <= top
19  where
20    bottom = min l r
21    top = max l r
22    result = fst (uniformR (l, r) g)
23
24singleton :: (RandomGen g, UniformRange a, Eq a) => Proxy a -> g -> a -> Bool
25singleton _ g x = result == x
26  where
27    result = fst (uniformR (x, x) g)
28
29uniformRangeWithin :: (RandomGen g, UniformRange a, Ord a) => Proxy a -> g -> (a, a) -> Bool
30uniformRangeWithin _ gen (l, r) =
31  runStateGen_ gen $ \g ->
32    (\result -> min l r <= result && result <= max l r) <$> uniformRM (l, r) g
33
34uniformRangeWithinExcludedF :: RandomGen g => g -> Bool
35uniformRangeWithinExcludedF gen =
36  runStateGen_ gen $ \g ->
37    (\result -> 0 < result && result <= 1) <$> uniformFloatPositive01M g
38
39uniformRangeWithinExcludedD :: RandomGen g => g -> Bool
40uniformRangeWithinExcludedD gen =
41  runStateGen_ gen $ \g ->
42    (\result -> 0 < result && result <= 1) <$> uniformDoublePositive01M g
43