99344b7 · text · git.iko.soy

git.iko.soy/text

Implement and test lazy head

--HG-- extra : convert_revision : cbdd5667b97c840d73ea553dac97d25b6966e503

commit99344b7224272749547a74a6124f3df30084f850 authorBryan O'Sullivan <bos@serpentine.com> dateSun 1 Mar 2009, 06:53 (18 years ago) parent6ec2765

2 files changed+11−1

compare with master

unifiedsplit

Data/Text/Lazy.hs+7−1 tests/Properties.hs+4

Data/Text/Lazy.hs+7−1

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

4444 , snoc

4545 , append

4646 , uncons

47− -- , head

47+ , head

4848 -- , last

4949 -- , tail

5050 -- , init

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

244244 if T.length t == 1 then ts else Chunk (T.unsafeTail t) ts)

245245{-# INLINE uncons #-}

246246

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+

247253-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a

248254-- prefix of @t@ of length @n@, and whose second is the remainder of

249255-- 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)

121121 where types = s :: String

122122prop_TL_uncons s = uncons `eqP` (fmap (second unpackT) . TL.uncons)

123123 where types = s :: String

124+prop_S_head = head `eqEP` S.head

124125prop_T_head = head `eqEP` T.head

126+prop_TL_head = head `eqEP` TL.head

125127prop_T_last = last `eqEP` T.last

126128prop_T_lastS = last `eqEP` (S.last . S.stream)

127129prop_T_tail = tail `eqEP` (unpackT . T.tail)

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

295297 ("prop_T_appendS", mytest prop_T_appendS),

296298 ("prop_T_uncons", mytest prop_T_uncons),

297299 ("prop_TL_uncons", mytest prop_TL_uncons),

300+ ("prop_S_head", mytest prop_S_head),

298301 ("prop_T_head", mytest prop_T_head),

302+ ("prop_TL_head", mytest prop_TL_head),

299303 ("prop_T_last", mytest prop_T_last),

300304 ("prop_T_lastS", mytest prop_T_lastS),

301305 ("prop_T_tail", mytest prop_T_tail),