9b61673 · text · git.iko.soy

git.iko.soy/text

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Add an unstreamed version of takeWhile

9b61673Bryan O'Sullivan18 years ago

Data/Text.hs+16−4

compare with master

unifiedsplit

@@ -598,11 +598,23 @@ drop n t@(Text arr off len)

598 unstream (S.drop n (stream t)) = drop n t

599 #-}

600

601−-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text', returns the

601+-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text', returns

602−-- longest prefix (possibly empty) of elements that satisfy @p@.

602+-- the longest prefix (possibly empty) of elements that satisfy @p@.

603+-- This function is subject to array fusion.

603takeWhile :: (Char -> Bool) -> Text -> Text

604takeWhile :: (Char -> Bool) -> Text -> Text

604−takeWhile p t = unstream (S.takeWhile p (stream t))

605+takeWhile p t@(Text arr off len) = loop off 0

606+ where loop !i !l | l >= len = t

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

608+ | otherwise = Text arr off l

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

610+{-# INLINE [1] takeWhile #-}

611+

612+{-# RULES

605−{-# INLINE takeWhile #-}

613+"TEXT takeWhile -> fused" [~1] forall p t.

614+ takeWhile p t = unstream (S.takeWhile p (stream t))

615+"TEXT takeWhile -> unfused" [1] forall p t.

616+ unstream (S.takeWhile p (stream t)) = takeWhile p t

617+ #-}

606

618

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

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

608-- 'takeWhile' @p@ @xs@.

620-- 'takeWhile' @p@ @xs@.

tests/Properties.hs+2

@@ -89,6 +89,7 @@ prop_unfoldrN n m = (L.take n . L.unfoldr f) `eq` (unpack . T.unfoldrN n f)

89prop_take n = L.take n `eqP` (unpack . T.take n)

90prop_drop n = L.drop n `eqP` (unpack . T.drop n)

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

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

92prop_dropWhile p = L.dropWhile p `eqP` (unpack . T.dropWhile p)

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

93prop_inits = L.inits `eqP` (map unpack . T.inits)

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

94prop_tails = L.tails `eqP` (map unpack . T.tails)

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

@@ -174,6 +175,7 @@ tests = [

174 ("prop_take", mytest prop_take),

175 ("prop_take", mytest prop_take),

175 ("prop_drop", mytest prop_drop),

176 ("prop_drop", mytest prop_drop),

176 ("prop_takeWhile", mytest prop_takeWhile),

177 ("prop_takeWhile", mytest prop_takeWhile),

178+ ("prop_takeWhileS", mytest prop_takeWhileS),

177 ("prop_dropWhile", mytest prop_dropWhile),

179 ("prop_dropWhile", mytest prop_dropWhile),

178 ("prop_inits", mytest prop_inits),

180 ("prop_inits", mytest prop_inits),

179 ("prop_tails", mytest prop_tails),

181 ("prop_tails", mytest prop_tails),