bbee394 · text · git.iko.soy

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Write a Text version of dropWhile

bbee394Bryan O'Sullivan18 years ago

Data/Text.hs+14−3

compare with master

unifiedsplit

@@ -617,10 +617,21 @@ takeWhile p t@(Text arr off len) = loop off 0

617 #-}

618

619-- | /O(n)/ 'dropWhile' @p@ @xs@ returns the suffix remaining after

620−-- 'takeWhile' @p@ @xs@.

620+-- 'takeWhile' @p@ @xs@. This function is subject to array fusion.

621dropWhile :: (Char -> Bool) -> Text -> Text

622−dropWhile p t = unstream (S.dropWhile p (stream t))

622+dropWhile p (Text arr off len) = loop off 0

623+ where loop !i !l | l >= len = empty

624+ | p c = loop (i+d) (l+d)

625+ | otherwise = Text arr i (len-l)

626+ where (c,d) = iter arr i

627+{-# INLINE [1] dropWhile #-}

628+

629+{-# RULES

623−{-# INLINE dropWhile #-}

630+"TEXT dropWhile -> fused" [~1] forall p t.

631+ dropWhile p t = unstream (S.dropWhile p (stream t))

632+"TEXT dropWhile -> unfused" [1] forall p t.

633+ unstream (S.dropWhile p (stream t)) = dropWhile p t

634+ #-}

624

635

625-- | /O(n)/ Return all initial segments of the given 'Text', shortest

636-- | /O(n)/ Return all initial segments of the given 'Text', shortest

626-- first.

637-- first.

tests/Properties.hs+2

@@ -91,6 +91,7 @@ prop_drop n = L.drop n `eqP` (unpack . T.drop n)

91prop_takeWhile p = L.takeWhile p `eqP` (unpack . T.takeWhile p)

92prop_takeWhileS p = L.takeWhile p `eqP` (unpack . unstream . S.takeWhile p . stream)

93prop_dropWhile p = L.dropWhile p `eqP` (unpack . T.dropWhile p)

94+prop_dropWhileS p = L.dropWhile p `eqP` (unpack . unstream . S.dropWhile p . stream)

94prop_inits = L.inits `eqP` (map unpack . T.inits)

95prop_inits = L.inits `eqP` (map unpack . T.inits)

95prop_tails = L.tails `eqP` (map unpack . T.tails)

96prop_tails = L.tails `eqP` (map unpack . T.tails)

@@ -177,6 +178,7 @@ tests = [

177 ("prop_takeWhile", mytest prop_takeWhile),

178 ("prop_takeWhile", mytest prop_takeWhile),

178 ("prop_takeWhileS", mytest prop_takeWhileS),

179 ("prop_takeWhileS", mytest prop_takeWhileS),

179 ("prop_dropWhile", mytest prop_dropWhile),

180 ("prop_dropWhile", mytest prop_dropWhile),

181+ ("prop_dropWhileS", mytest prop_dropWhileS),

180 ("prop_inits", mytest prop_inits),

182 ("prop_inits", mytest prop_inits),

181 ("prop_tails", mytest prop_tails),

183 ("prop_tails", mytest prop_tails),

182

184