0c2ff73 · text · git.iko.soy

git.iko.soy/text

Merge pull request #111 from RyanGlScott/master

Implement repeat, cycle, iterate for lazy Texts

commit0c2ff73b26e997c1a04b7e08e0b4376b7c30d002 authorBryan O'Sullivan <bos@serpentine.com> dateTue 17 Feb 2015, 22:03 (12 years ago) parent1e3ae85 b8ff30a

2 files changed+41−1

compare with master

unifiedsplit

Data/Text/Lazy.hs+26−1 tests/Tests/Properties.hs+15

Data/Text/Lazy.hs+26−1

@@ -125,7 +125,10 @@ module Data.Text.Lazy

125125 , mapAccumR

126126

127127 -- ** Generation and unfolding

128+ , repeat

128129 , replicate

130+ , cycle

131+ , iterate

129132 , unfoldr

130133 , unfoldrN

131134

@@ -218,7 +221,8 @@ import qualified Data.Text.Unsafe as T

218221import qualified Data.Text.Internal.Lazy.Fusion as S

219222import Data.Text.Internal.Fusion.Types (PairS(..))

220223import Data.Text.Internal.Lazy.Fusion (stream, unstream)

221−import Data.Text.Internal.Lazy (Text(..), chunk, empty, foldlChunks, foldrChunks)

224+import Data.Text.Internal.Lazy (Text(..), chunk, empty, foldlChunks,

225+ foldrChunks, smallChunkSize)

222226import Data.Text.Internal (firstf, safe, text)

223227import qualified Data.Text.Internal.Functions as F

224228import Data.Text.Internal.Lazy.Search (indices)

@@ -918,6 +922,12 @@ mapAccumR f = go

918922 go z Empty = (z, Empty)

919923{-# INLINE mapAccumR #-}

920924

925+-- | @'repeat' x@ is an infinite 'Text', with @x@ the value of every

926+-- element.

927+repeat :: Char -> Text

928+repeat c = let t = Chunk (T.replicate smallChunkSize (T.singleton c)) t

929+ in t

930+

921931-- | /O(n*m)/ 'replicate' @n@ @t@ is a 'Text' consisting of the input

922932-- @t@ repeated @n@ times.

923933replicate :: Int64 -> Text -> Text

@@ -929,6 +939,21 @@ replicate n t

929939 | otherwise = t : rep (i+1)

930940{-# INLINE [1] replicate #-}

931941

942+-- | 'cycle' ties a finite, non-empty 'Text' into a circular one, or

943+-- equivalently, the infinite repetition of the original 'Text'.

944+cycle :: Text -> Text

945+cycle Empty = emptyError "cycle"

946+cycle t = let t' = foldrChunks Chunk t' t

947+ in t'

948+

949+-- | @'iterate' f x@ returns an infinite 'Text' of repeated applications

950+-- of @f@ to @x@:

951+--

952+-- > iterate f x == [x, f x, f (f x), ...]

953+iterate :: (Char -> Char) -> Char -> Text

954+iterate f c = let t c' = Chunk (T.singleton c') (t (f c'))

955+ in t c

956+

932957-- | /O(n)/ 'replicateChar' @n@ @c@ is a 'Text' of length @n@ with @c@ the

933958-- value of every element. Subject to fusion.

934959replicateChar :: Int64 -> Char -> Text

tests/Tests/Properties.hs+15

@@ -440,6 +440,10 @@ t_mapAccumR f z = L.mapAccumR f z `eqP` (second unpackS . T.mapAccumR f z)

440440tl_mapAccumR f z = L.mapAccumR f z `eqP` (second unpackS . TL.mapAccumR f z)

441441 where _types = f :: Int -> Char -> (Int,Char)

442442

443+tl_repeat n = (L.take m . L.repeat) `eq`

444+ (unpackS . TL.take (fromIntegral m) . TL.repeat)

445+ where m = fromIntegral (n :: Word8)

446+

443447replicate n l = concat (L.replicate n l)

444448

445449s_replicate n = replicate m `eq`

@@ -451,6 +455,14 @@ tl_replicate n = replicate m `eq`

451455 (unpackS . TL.replicate (fromIntegral m) . packS)

452456 where m = fromIntegral (n :: Word8)

453457

458+tl_cycle n = (L.take m . L.cycle) `eq`

459+ (unpackS . TL.take (fromIntegral m) . TL.cycle . packS)

460+ where m = fromIntegral (n :: Word8)

461+

462+tl_iterate f n = (L.take m . L.iterate f) `eq`

463+ (unpackS . TL.take (fromIntegral m) . TL.iterate f)

464+ where m = fromIntegral (n :: Word8)

465+

454466unf :: Int -> Char -> Maybe (Char, Char)

455467unf n c | fromEnum c * 100 > n = Nothing

456468 | otherwise = Just (c, succ c)

@@ -1094,9 +1106,12 @@ tests =

10941106 ],

10951107

10961108 testGroup "unfolds" [

1109+ testProperty "tl_repeat" tl_repeat,

10971110 testProperty "s_replicate" s_replicate,

10981111 testProperty "t_replicate" t_replicate,

10991112 testProperty "tl_replicate" tl_replicate,

1113+ testProperty "tl_cycle" tl_cycle,

1114+ testProperty "tl_iterate" tl_iterate,

11001115 testProperty "t_unfoldr" t_unfoldr,

11011116 testProperty "tl_unfoldr" tl_unfoldr,

11021117 testProperty "t_unfoldrN" t_unfoldrN,