26830b5 · text · git.iko.soy

git.iko.soy/text

Implement isPrefixOf

Still need to write fused version --HG-- extra : convert_revision : 9d238e05aa4d52e77ba4f2bf997e56b9cb7d26df

commit26830b55383b3ef777a27a3e3ce72c67bb47ee09 authorBryan O'Sullivan <bos@serpentine.com> dateWed 11 Feb 2009, 07:30 (18 years ago) parent3b523ff

2 files changed+15−2

compare with master

unifiedsplit

Data/Text.hs+11−2 tests/Properties.hs+4

Data/Text.hs+11−2

@@ -115,7 +115,7 @@ module Data.Text

115115 , unwords

116116

117117 -- * Predicates

118− -- , isPrefixOf

118+ , isPrefixOf

119119 -- , isSuffixOf

120120 -- , isInfixOf

121121

@@ -143,7 +143,7 @@ module Data.Text

143143 , -- sort

144144 ) where

145145

146−import Prelude (Char, Bool, Functor(..), Int, Maybe(..), String,

146+import Prelude (Char, Bool(..), Functor(..), Int, Maybe(..), String,

147147 Eq, (==), (++), error,

148148 Read(..), Show(..),

149149 (&&), (||), (+), (-), (<), (>), (<=), (>=), (.), ($),

@@ -836,5 +836,14 @@ unwords :: [Text] -> Text

836836unwords = intercalate (singleton ' ')

837837{-# INLINE unwords #-}

838838

839+isPrefixOf :: 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

846+{-# INLINE [1] isPrefixOf #-}

847+

839848errorEmptyList :: String -> a

840849errorEmptyList fun = error ("Data.Text." ++ fun ++ ": empty list")

tests/Properties.hs+4

@@ -140,6 +140,8 @@ prop_words = L.words `eqP` (map unpack . T.words)

140140prop_unlines = L.unlines `eq` (unpack . T.unlines . map pack)

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

142142

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

144+

143145prop_elem c = L.elem c `eqP` T.elem c

144146prop_filter p = L.filter p `eqP` (unpack . T.filter p)

145147prop_find p = L.find p `eqP` T.find p

@@ -235,6 +237,8 @@ tests = [

235237 ("prop_unlines", mytest prop_unlines),

236238 ("prop_unwords", mytest prop_unwords),

237239

240+ ("prop_isPrefixOf", mytest prop_isPrefixOf),

241+

238242 ("prop_elem", mytest prop_elem),

239243 ("prop_filter", mytest prop_filter),

240244 ("prop_find", mytest prop_find),