1fde6e9 · text · git.iko.soy

git.iko.soy/text

on master help sign in

Implement and test lazy scanr1

1fde6e9Bryan O'Sullivan18 years ago

Data/Text/Lazy.hs+7−1

compare with master

unifiedsplit

@@ -82,7 +82,7 @@ module Data.Text.Lazy

82 , scanl

83 , scanl1

84 , scanr

85− -- , scanr1

85+ , scanr1

87 -- ** Accumulating maps

88 , mapAccumL

@@ -478,6 +478,12 @@ scanl1 f t0 = case uncons t0 of

478scanr :: (Char -> Char -> Char) -> Char -> Text -> Text

479scanr f v = reverse . scanl (flip f) v . reverse

480

481+-- | /O(n)/ 'scanr1' is a variant of 'scanr' that has no starting

482+-- value argument.

483+scanr1 :: (Char -> Char -> Char) -> Text -> Text

484+scanr1 f t | null t = empty

485+ | otherwise = scanr f (last t) (init t)

486+

481-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a

487-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a

482-- function to each element of a 'Text', passing an accumulating

488-- function to each element of a 'Text', passing an accumulating

483-- parameter from left to right, and returns a final 'Text'.

489-- parameter from left to right, and returns a final 'Text'.

tests/Properties.hs+2

@@ -206,6 +206,7 @@ prop_TL_scanl1 f = L.scanl1 f `eqP` (unpackT . TL.scanl1 f)

206prop_T_scanr f z = L.scanr f z `eqP` (unpackT . T.scanr f z)

207prop_TL_scanr f z = L.scanr f z `eqP` (unpackT . TL.scanr f z)

208prop_T_scanr1 f = L.scanr1 f `eqP` (unpackT . T.scanr1 f)

209+prop_TL_scanr1 f = L.scanr1 f `eqP` (unpackT . TL.scanr1 f)

209

210

210prop_T_mapAccumL f z = L.mapAccumL f z `eqP` (second unpackT . T.mapAccumL f z)

211prop_T_mapAccumL f z = L.mapAccumL f z `eqP` (second unpackT . T.mapAccumL f z)

211 where types = f :: Int -> Char -> (Int,Char)

212 where types = f :: Int -> Char -> (Int,Char)

@@ -435,6 +436,7 @@ tests = [

435 ("prop_T_scanr", mytest prop_T_scanr),

436 ("prop_T_scanr", mytest prop_T_scanr),

436 ("prop_TL_scanr", mytest prop_TL_scanr),

437 ("prop_TL_scanr", mytest prop_TL_scanr),

437 ("prop_T_scanr1", mytest prop_T_scanr1),

438 ("prop_T_scanr1", mytest prop_T_scanr1),

439+ ("prop_TL_scanr1", mytest prop_TL_scanr1),

438

440

439 ("prop_T_mapAccumL", mytest prop_T_mapAccumL),

441 ("prop_T_mapAccumL", mytest prop_T_mapAccumL),

440 ("prop_TL_mapAccumL", mytest prop_TL_mapAccumL),

442 ("prop_TL_mapAccumL", mytest prop_TL_mapAccumL),