b895b63 · text · git.iko.soy

git.iko.soy/text

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Implement and test lazy tail

b895b63Bryan O'Sullivan18 years ago

Data/Text/Lazy.hs+13−1

compare with master

unifiedsplit

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

46 , uncons

47 , head

48 , last

49− -- , tail

49+ , tail

50 -- , init

51 -- , null

52 -- , length

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

251head t = S.head (stream t)

252{-# INLINE head #-}

253

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+

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

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

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

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

256last :: Text -> Char

268last :: Text -> Char

tests/Properties.hs+4−2

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

127prop_S_last = last `eqEP` S.last

128prop_T_last = last `eqEP` T.last

129prop_TL_last = last `eqEP` TL.last

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

130prop_T_tail = tail `eqEP` (unpackT . T.tail)

131prop_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)

132prop_T_init = init `eqEP` (unpackT . T.init)

133prop_T_init = init `eqEP` (unpackT . T.init)

133prop_T_initS = init `eqEP` (unpackT . S.unstream . S.init . S.stream)

134prop_T_initS = init `eqEP` (unpackT . S.unstream . S.init . S.stream)

134prop_T_null = null `eqP` T.null

135prop_T_null = null `eqP` T.null

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

304 ("prop_S_last", mytest prop_S_last),

305 ("prop_S_last", mytest prop_S_last),

305 ("prop_T_last", mytest prop_T_last),

306 ("prop_T_last", mytest prop_T_last),

306 ("prop_TL_last", mytest prop_TL_last),

307 ("prop_TL_last", mytest prop_TL_last),

308+ ("prop_S_tail", mytest prop_S_tail),

307 ("prop_T_tail", mytest prop_T_tail),

309 ("prop_T_tail", mytest prop_T_tail),

308− ("prop_T_tailS", mytest prop_T_tailS),

310+ ("prop_TL_tail", mytest prop_TL_tail),

309 ("prop_T_init", mytest prop_T_init),

311 ("prop_T_init", mytest prop_T_init),

310 ("prop_T_initS", mytest prop_T_initS),

312 ("prop_T_initS", mytest prop_T_initS),

311 ("prop_T_null", mytest prop_T_null),

313 ("prop_T_null", mytest prop_T_null),