b895b63 · text · git.iko.soy

git.iko.soy/text

Implement and test lazy tail

--HG-- extra : convert_revision : 077b516d8b5b0fc44ce8373f604a876b4626e1a9

commitb895b6358aad5918c03e816ada01237579a09b42 authorBryan O'Sullivan <bos@serpentine.com> dateTue 3 Mar 2009, 00:09 (18 years ago) parentd581176

2 files changed+17−3

compare with master

unifiedsplit

Data/Text/Lazy.hs+13−1 tests/Properties.hs+4−2

Data/Text/Lazy.hs+13−1

@@ -46,7 +46,7 @@ module Data.Text.Lazy

4646 , uncons

4747 , head

4848 , last

49− -- , tail

49+ , tail

5050 -- , init

5151 -- , null

5252 -- , length

@@ -251,6 +251,18 @@ head :: Text -> Char

251251head t = S.head (stream t)

252252{-# INLINE head #-}

253253

254+tail :: Text -> Text

255+tail (Chunk t ts) = chunk (T.tail t) ts

256+tail Empty = emptyError "tail"

257+{-# INLINE [1] tail #-}

258+

259+{-# RULES

260+"TEXT tail -> fused" [~1] forall t.

261+ tail t = unstream (S.tail (stream t))

262+"TEXT tail -> unfused" [1] forall t.

263+ unstream (S.tail (stream t)) = tail t

264+ #-}

265+

254266-- | /O(1)/ Returns the last character of a 'Text', which must be

255267-- non-empty. Subject to array fusion.

256268last :: Text -> Char

tests/Properties.hs+4−2

@@ -127,8 +127,9 @@ prop_TL_head = head `eqEP` TL.head

127127prop_S_last = last `eqEP` S.last

128128prop_T_last = last `eqEP` T.last

129129prop_TL_last = last `eqEP` TL.last

130+prop_S_tail = tail `eqEP` (unpackT . S.tail)

130131prop_T_tail = tail `eqEP` (unpackT . T.tail)

131−prop_T_tailS = tail `eqEP` (unpackT . S.unstream . S.tail . S.stream)

132+prop_TL_tail = tail `eqEP` (unpackT . TL.tail)

132133prop_T_init = init `eqEP` (unpackT . T.init)

133134prop_T_initS = init `eqEP` (unpackT . S.unstream . S.init . S.stream)

134135prop_T_null = null `eqP` T.null

@@ -304,8 +305,9 @@ tests = [

304305 ("prop_S_last", mytest prop_S_last),

305306 ("prop_T_last", mytest prop_T_last),

306307 ("prop_TL_last", mytest prop_TL_last),

308+ ("prop_S_tail", mytest prop_S_tail),

307309 ("prop_T_tail", mytest prop_T_tail),

308− ("prop_T_tailS", mytest prop_T_tailS),

310+ ("prop_TL_tail", mytest prop_TL_tail),

309311 ("prop_T_init", mytest prop_T_init),

310312 ("prop_T_initS", mytest prop_T_initS),

311313 ("prop_T_null", mytest prop_T_null),