aa77840 · text · git.iko.soy

git.iko.soy/text

Replace isPrefix implementation with streamed version

--HG-- extra : convert_revision : bc2a647211a4d913f7e12b97faa2c944cb56ac2e

commitaa778400dc674cd64baddd189298ad2d265a82e1 authorBryan O'Sullivan <bos@serpentine.com> dateThu 12 Feb 2009, 07:10 (18 years ago) parent26830b5

3 files changed+28−6

compare with master

unifiedsplit

Data/Text.hs+9−6 Data/Text/Fusion.hs+17 tests/Properties.hs+2

Data/Text.hs+9−6

@@ -837,13 +837,16 @@ unwords = intercalate (singleton ' ')

837837{-# INLINE unwords #-}

838838

839839isPrefixOf :: Text -> Text -> Bool

840−isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) = alen <= blen && loop 0 0

841− where loop !i !j | i >= alen = True

842− | c == e = loop (i+d) (j+f)

843− | otherwise = False

844− where (c,d) = iter a i

845− (e,f) = iter b j

840+isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =

841+ alen <= blen && S.isPrefixOf (stream a) (stream b)

846842{-# INLINE [1] isPrefixOf #-}

847843

844+{-# RULES

845+"TEXT isPrefixOf -> fused" [~1] forall s t.

846+ isPrefixOf s t = S.isPrefixOf (stream s) (stream t)

847+"TEXT isPrefixOf -> unfused" [1] forall s t.

848+ S.isPrefixOf (stream s) (stream t) = isPrefixOf s t

849+ #-}

850+

848851errorEmptyList :: String -> a

849852errorEmptyList fun = error ("Data.Text." ++ fun ++ ": empty list")

Data/Text/Fusion.hs+17

@@ -79,6 +79,9 @@ module Data.Text.Fusion

7979 , takeWhile

8080 , dropWhile

8181

82+ -- * Predicates

83+ , isPrefixOf

84+

8285 -- * Searching

8386 , elem

8487 , filter

@@ -683,6 +686,19 @@ dropWhile p (Stream next0 s0 len) = Stream next (S1 :!: s0) len

683686 Yield x s' -> Yield x (S2 :!: s')

684687{-# INLINE [0] dropWhile #-}

685688

689+isPrefixOf :: (Eq a) => Stream a -> Stream a -> Bool

690+isPrefixOf (Stream next1 s1 _) (Stream next2 s2 _) = loop (next1 s1) (next2 s2)

691+ where

692+ loop Done _ = True

693+ loop _ Done = False

694+ loop (Skip s1') (Skip s2') = loop (next1 s1') (next2 s2')

695+ loop (Skip s1') x2 = loop (next1 s1') x2

696+ loop x1 (Skip s2') = loop x1 (next2 s2')

697+ loop (Yield x1 s1') (Yield x2 s2') = x1 == x2 &&

698+ loop (next1 s1') (next2 s2')

699+{-# INLINE [0] isPrefixOf #-}

700+{-# SPECIALISE isPrefixOf :: Stream Char -> Stream Char -> Bool #-}

701+

686702-- ----------------------------------------------------------------------------

687703-- * Searching

688704

@@ -811,5 +827,6 @@ zipWith f (Stream next0 sa0 len1) (Stream next1 sb0 len2) = Stream next (sa0 :!:

811827 Yield b sb' -> Yield (f a b) (sa' :!: sb' :!: Nothing)

812828{-# INLINE [0] zipWith #-}

813829

830+

814831errorEmptyList :: String -> a

815832errorEmptyList fun = error ("Data.Text.Fusion." ++ fun ++ ": empty list")

tests/Properties.hs+2

@@ -141,6 +141,7 @@ prop_unlines = L.unlines `eq` (unpack . T.unlines . map pack)

141141prop_unwords = L.unwords `eq` (unpack . T.unwords . map pack)

142142

143143prop_isPrefixOf s = L.isPrefixOf s`eqP` T.isPrefixOf (pack s)

144+prop_isPrefixOfS s = L.isPrefixOf s`eqP` (S.isPrefixOf (stream $ pack s) . stream)

144145

145146prop_elem c = L.elem c `eqP` T.elem c

146147prop_filter p = L.filter p `eqP` (unpack . T.filter p)

@@ -238,6 +239,7 @@ tests = [

238239 ("prop_unwords", mytest prop_unwords),

239240

240241 ("prop_isPrefixOf", mytest prop_isPrefixOf),

242+ ("prop_isPrefixOfS", mytest prop_isPrefixOfS),

241243

242244 ("prop_elem", mytest prop_elem),

243245 ("prop_filter", mytest prop_filter),