99344b7 · text · git.iko.soy

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Implement and test lazy head

99344b7Bryan O'Sullivan18 years ago

Data/Text/Lazy.hs+7−1

compare with master

unifiedsplit

@@ -44,7 +44,7 @@ module Data.Text.Lazy

44 , snoc

45 , append

46 , uncons

47− -- , head

47+ , head

48 -- , last

49 -- , tail

50 -- , init

@@ -244,6 +244,12 @@ uncons (Chunk t ts) =

244 if T.length t == 1 then ts else Chunk (T.unsafeTail t) ts)

245{-# INLINE uncons #-}

246

247+-- | /O(1)/ Returns the first character of a 'Text', which must be

248+-- non-empty. Subject to array fusion.

249+head :: Text -> Char

250+head t = S.head (stream t)

251+{-# INLINE head #-}

252+

247-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a

253-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a

248-- prefix of @t@ of length @n@, and whose second is the remainder of

254-- prefix of @t@ of length @n@, and whose second is the remainder of

249-- the string. It is equivalent to @('take' n t, 'drop' n t)@.

255-- the string. It is equivalent to @('take' n t, 'drop' n t)@.

tests/Properties.hs+4

@@ -121,7 +121,9 @@ prop_T_uncons s = uncons `eqP` (fmap (second unpackT) . T.uncons)

121 where types = s :: String

122prop_TL_uncons s = uncons `eqP` (fmap (second unpackT) . TL.uncons)

123 where types = s :: String

124+prop_S_head = head `eqEP` S.head

124prop_T_head = head `eqEP` T.head

125prop_T_head = head `eqEP` T.head

126+prop_TL_head = head `eqEP` TL.head

125prop_T_last = last `eqEP` T.last

127prop_T_last = last `eqEP` T.last

126prop_T_lastS = last `eqEP` (S.last . S.stream)

128prop_T_lastS = last `eqEP` (S.last . S.stream)

127prop_T_tail = tail `eqEP` (unpackT . T.tail)

129prop_T_tail = tail `eqEP` (unpackT . T.tail)

@@ -295,7 +297,9 @@ tests = [

295 ("prop_T_appendS", mytest prop_T_appendS),

297 ("prop_T_appendS", mytest prop_T_appendS),

296 ("prop_T_uncons", mytest prop_T_uncons),

298 ("prop_T_uncons", mytest prop_T_uncons),

297 ("prop_TL_uncons", mytest prop_TL_uncons),

299 ("prop_TL_uncons", mytest prop_TL_uncons),

300+ ("prop_S_head", mytest prop_S_head),

298 ("prop_T_head", mytest prop_T_head),

301 ("prop_T_head", mytest prop_T_head),

302+ ("prop_TL_head", mytest prop_TL_head),

299 ("prop_T_last", mytest prop_T_last),

303 ("prop_T_last", mytest prop_T_last),

300 ("prop_T_lastS", mytest prop_T_lastS),

304 ("prop_T_lastS", mytest prop_T_lastS),

301 ("prop_T_tail", mytest prop_T_tail),

305 ("prop_T_tail", mytest prop_T_tail),