7541131 · text · git.iko.soy

git.iko.soy/text

Implement and test scanl1

--HG-- extra : convert_revision : b9d9328622e3bef8ac11f2af08f39e702f0c5b14

commit7541131a2a58af0a21ac203d00614f7b0716678f authorBryan O'Sullivan <bos@serpentine.com> dateTue 3 Feb 2009, 22:33 (18 years ago) parent8ba69d7

2 files changed+12−1

compare with master

unifiedsplit

Data/Text.hs+10−1 tests/Properties.hs+2

Data/Text.hs+10−1

@@ -75,7 +75,7 @@ module Data.Text

7575

7676 -- ** Scans

7777 , scanl

78− -- , scanl1

78+ , scanl1

7979 -- , scanr

8080 -- , scanr1

8181

@@ -495,6 +495,15 @@ scanl :: (Char -> Char -> Char) -> Char -> Text -> Text

495495scanl f z t = unstream (S.scanl f z (stream t))

496496{-# INLINE scanl #-}

497497

498+-- | /O(n)/ 'scanl1' is a variant of 'scanl' that has no starting

499+-- value argument. This function is subject to array fusion.

500+--

501+-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]

502+scanl1 :: (Char -> Char -> Char) -> Text -> Text

503+scanl1 f t | null t = empty

504+ | otherwise = scanl f (head t) (tail t)

505+{-# INLINE scanl1 #-}

506+

498507-- -----------------------------------------------------------------------------

499508-- ** Generating and unfolding 'Text's

500509

tests/Properties.hs+2

@@ -72,6 +72,7 @@ prop_maximum = L.maximum `eqEP` T.maximum

7272prop_minimum = L.minimum `eqEP` T.minimum

7373

7474prop_scanl f z = L.scanl f z `eqP` (unpack . T.scanl f z)

75+prop_scanl1 f = L.scanl1 f `eqP` (unpack . T.scanl1 f)

7576

7677prop_replicate n = L.replicate n `eq` (unpack . T.replicate n)

7778prop_unfoldr n = L.unfoldr f `eq` (unpack . T.unfoldr f)

@@ -159,6 +160,7 @@ tests = [

159160 ("prop_minimum", mytest prop_minimum),

160161

161162 ("prop_scanl", mytest prop_scanl),

163+ ("prop_scanl1", mytest prop_scanl1),

162164

163165 ("prop_replicate", mytest prop_replicate),

164166 ("prop_unfoldr", mytest prop_unfoldr),