blob: f2adda393abf461a0cdb80583b4066af18e79baf (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
{-|
Module : Test.VeriFuzz.Internal.Shared
Description : Shared high level code used in the other modules internally.
Copyright : (c) 2018-2019, Yann Herklotz Grave
License : BSD-3
Maintainer : ymherklotz [at] gmail [dot] com
Stability : experimental
Portability : POSIX
Shared high level code used in the other modules internally.
-}
module Test.VeriFuzz.Internal.Shared where
import Data.Maybe (fromMaybe)
-- | Fold up a list of Monoids using mappend and mempty as the first
-- element.
fromList :: (Foldable t, Monoid a) => t a -> a
fromList = foldl mappend mempty
-- | Combine the Monoid elements of a list and insert the seperation symbol in
-- between each element except the last one.
sep :: (Monoid a) => a -> [a] -> a
sep el l = fromMaybe mempty $
(fromList . fmap (<>el) <$> safe init l) <> safe last l
-- | Converts unsafe list functions in the Prelude to a safe version.
safe :: ([a] -> b) -> [a] -> Maybe b
safe _ [] = Nothing
safe f l = Just $ f l
|
