{-# LANGUAGE RankNTypes, TypeFamilies, BangPatterns, Trustworthy #-}
-{-| This package provides @pipes@ utilities for \'text streams\', which are
- streams of 'Text' chunks. The individual chunks are uniformly @strict@, and you
- will generally want @Data.Text@ in scope. But the type @Producer Text m r@ is
- in some ways the pipes equivalent of the lazy @Text@ type.
-
- This module provides many functions equivalent in one way or another to
- the 'pure' functions in
- <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>.
- They transform, divide, group and fold text streams. Though @Producer Text m r@
- is \'effectful\' Text, functions
- in this module are \'pure\' in the sense that they are uniformly monad-independent.
- Simple IO operations are defined in @Pipes.Text.IO@ -- as lazy IO @Text@
- operations are in @Data.Text.Lazy.IO@. Interoperation with @ByteString@
- is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@.
-
- The Text type exported by @Data.Text.Lazy@ is basically '[Text]'. The implementation
- is arranged so that the individual strict 'Text' chunks are kept to a reasonable size;
- the user is not aware of the divisions between the connected 'Text' chunks.
- So also here: the functions in this module are designed to operate on streams that
- are insensitive to text boundaries. This means that they may freely split
- text into smaller texts and /discard empty texts/. However, the objective is
- that they should /never concatenate texts/ in order to provide strict upper
- bounds on memory usage.
-
- For example, to stream only the first three lines of 'stdin' to 'stdout' you
- might write:
-
-> import Pipes
-> import qualified Pipes.Text as Text
-> import qualified Pipes.Text.IO as Text
-> import Pipes.Group
-> import Lens.Family
->
-> main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout
-> where
-> takeLines n = Text.unlines . takes' n . view Text.lines
-> -- or equivalently:
-> -- takeLines n = over Text.lines (takes' n)
-
- The above program will never bring more than one chunk of text (~ 32 KB) into
- memory, no matter how long the lines are.
-
- As this example shows, one superficial difference from @Data.Text.Lazy@
- is that many of the operations, like 'lines',
- are \'lensified\'; this has a number of advantages where it is possible, in particular
- it facilitates their use with 'Parser's of Text (in the general
- <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html pipes-parse>
- sense.)
- Each such expression, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the
- intuitively corresponding function when used with @view@ or @(^.)@.
-
- A more important difference the example reveals is in the types closely associated with
- the central type, @Producer Text m r@. In @Data.Text@ and @Data.Text.Lazy@
- we find functions like
-
-> splitAt :: Int -> Text -> (Text, Text)
-> lines :: Int -> Text -> [Text]
-> chunksOf :: Int -> Text -> [Text]
-
- which relate a Text with a pair or list of Texts. The corresponding functions here (taking
- account of \'lensification\') are
-
-> view . splitAt :: (Monad m, Integral n)
-> => n -> Producer Text m r -> Producer Text.Text m (Producer Text.Text m r)
-> view lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r
-> view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r
-
- In the type @Producer Text m (Producer Text m r)@ the second
- element of the \'pair\' of of \'effectful Texts\' cannot simply be retrieved
- with 'snd'. This is an \'effectful\' pair, and one must work through the effects
- of the first element to arrive at the second. Similarly in @FreeT (Producer Text m) m r@,
- which corresponds with @[Text]@, on cannot simply drop 10 Producers and take the others;
- we can only get to the ones we want to take by working through their predecessors.
-
- Some of the types may be more readable if you imagine that we have introduced
- our own type synonyms
-
-> type Text m r = Producer T.Text m r
-> type Texts m r = FreeT (Producer T.Text m) m r
-
- Then we would think of the types above as
-
-> view . splitAt :: (Monad m, Integral n) => n -> Text m r -> Text m (Text m r)
-> view lines :: (Monad m) => Text m r -> Texts m r
-> view . chunksOf :: (Monad m, Integral n) => n -> Text m r -> Texts m r
-
- which brings one closer to the types of the similar functions in @Data.Text.Lazy@
-
+{-| The module @Pipes.Text@ closely follows @Pipes.ByteString@ from
+ the @pipes-bytestring@ package. A draft tutorial can be found in
+ @Pipes.Text.Tutorial@.
-}
module Pipes.Text (
, map
, concatMap
, take
- , drop
, takeWhile
- , dropWhile
, filter
- , scan
- , pack
- , unpack
, toCaseFold
, toLower
, toUpper
, stripStart
+ , scan
-- * Folds
, toLazy
, minimum
, find
, index
- , count
-- * Primitive Character Parsers
, nextChar
, peekChar
, isEndOfChars
- -- * Parsing Lenses
+ -- * Parsing Lenses
, splitAt
, span
, break
, word
, line
- -- * FreeT Splitters
+ -- * Transforming Text and Character Streams
+ , drop
+ , dropWhile
+ , pack
+ , unpack
+ , intersperse
+
+ -- * FreeT Transformations
, chunksOf
, splitsWith
, splits
, groupsBy
, groups
, lines
- , words
-
- -- * Transformations
- , intersperse
- , packChars
-
- -- * Joiners
- , intercalate
, unlines
+ , words
, unwords
+ , intercalate
-- * Re-exports
-- $reexports
, module Data.ByteString
, module Data.Text
- , module Data.Profunctor
, module Pipes.Parse
, module Pipes.Group
) where
-import Control.Applicative ((<*))
+import Control.Applicative ((<*))
import Control.Monad (liftM, join)
import Control.Monad.Trans.State.Strict (StateT(..), modify)
import qualified Data.Text as T
import Data.Text (Text)
import qualified Data.Text.Lazy as TL
-import Data.Text.Lazy.Internal (foldrChunks, defaultChunkSize)
import Data.ByteString (ByteString)
import Data.Functor.Constant (Constant(Constant, getConstant))
import Data.Functor.Identity (Identity)
-import Data.Profunctor (Profunctor)
-import qualified Data.Profunctor
+
import Pipes
-import Pipes.Group (concats, intercalates, FreeT(..), FreeF(..))
+import Pipes.Group (folds, maps, concats, intercalates, FreeT(..), FreeF(..))
import qualified Pipes.Group as PG
import qualified Pipes.Parse as PP
import Pipes.Parse (Parser)
import qualified Pipes.Prelude as P
import Data.Char (isSpace)
import Data.Word (Word8)
-
+import Foreign.Storable (sizeOf)
+import Data.Bits (shiftL)
import Prelude hiding (
all,
any,
words,
writeFile )
--- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's
+-- $setup
+-- >>> :set -XOverloadedStrings
+-- >>> import Data.Text (Text)
+-- >>> import qualified Data.Text as T
+-- >>> import qualified Data.Text.Lazy.IO as TL
+-- >>> import Data.Char
+
+-- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's. Producers in
+-- IO can be found in 'Pipes.Text.IO' or in pipes-bytestring, employed with the
+-- decoding lenses in 'Pipes.Text.Encoding'
fromLazy :: (Monad m) => TL.Text -> Producer' Text m ()
-fromLazy = foldrChunks (\e a -> yield e >> a) (return ())
+fromLazy = TL.foldrChunks (\e a -> yield e >> a) (return ())
{-# INLINE fromLazy #-}
-
-type Lens' a b = forall f . Functor f => (b -> f b) -> (a -> f a)
-
-type Iso' a b = forall f p . (Functor f, Profunctor p) => p b (f b) -> p a (f a)
-
(^.) :: a -> ((b -> Constant b b) -> (a -> Constant b a)) -> b
a ^. lens = getConstant (lens Constant a)
-
-- | Apply a transformation to each 'Char' in the stream
+
+-- >>> let margaret = ["Margaret, are you grieving\nOver Golde","ngrove unleaving?":: Text]
+-- >>> TL.putStrLn . toLazy $ each margaret >-> map Data.Char.toUpper
+-- MARGARET, ARE YOU GRIEVING
+-- OVER GOLDENGROVE UNLEAVING?
map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r
map f = P.map (T.map f)
{-# INLINABLE map #-}
-{-# RULES "p >-> map f" forall p f .
- p >-> map f = for p (\txt -> yield (T.map f txt))
- #-}
-
-- | Map a function over the characters of a text stream and concatenate the results
+
concatMap
:: (Monad m) => (Char -> Text) -> Pipe Text Text m r
concatMap f = P.map (T.concatMap f)
{-# INLINABLE concatMap #-}
-{-# RULES "p >-> concatMap f" forall p f .
- p >-> concatMap f = for p (\txt -> yield (T.concatMap f txt))
- #-}
-
-
--- | Transform a Pipe of 'String's into one of 'Text' chunks
-pack :: Monad m => Pipe String Text m r
-pack = P.map T.pack
-{-# INLINEABLE pack #-}
-
-{-# RULES "p >-> pack" forall p .
- p >-> pack = for p (\txt -> yield (T.pack txt))
- #-}
-
--- | Transform a Pipes of 'Text' chunks into one of 'String's
-unpack :: Monad m => Pipe Text String m r
-unpack = for cat (\t -> yield (T.unpack t))
-{-# INLINEABLE unpack #-}
-
-{-# RULES "p >-> unpack" forall p .
- p >-> unpack = for p (\txt -> yield (T.unpack txt))
- #-}
-
--- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utilities,
--- here acting as 'Text' pipes, rather as they would on a lazy text
-toCaseFold :: Monad m => Pipe Text Text m ()
-toCaseFold = P.map T.toCaseFold
-{-# INLINEABLE toCaseFold #-}
-
-{-# RULES "p >-> toCaseFold" forall p .
- p >-> toCaseFold = for p (\txt -> yield (T.toCaseFold txt))
- #-}
-
-
--- | lowercase incoming 'Text'
-toLower :: Monad m => Pipe Text Text m ()
-toLower = P.map T.toLower
-{-# INLINEABLE toLower #-}
-
-{-# RULES "p >-> toLower" forall p .
- p >-> toLower = for p (\txt -> yield (T.toLower txt))
- #-}
-
--- | uppercase incoming 'Text'
-toUpper :: Monad m => Pipe Text Text m ()
-toUpper = P.map T.toUpper
-{-# INLINEABLE toUpper #-}
-
-{-# RULES "p >-> toUpper" forall p .
- p >-> toUpper = for p (\txt -> yield (T.toUpper txt))
- #-}
-
--- | Remove leading white space from an incoming succession of 'Text's
-stripStart :: Monad m => Pipe Text Text m r
-stripStart = do
- chunk <- await
- let text = T.stripStart chunk
- if T.null text
- then stripStart
- else do yield text
- cat
-{-# INLINEABLE stripStart #-}
-
--- | @(take n)@ only allows @n@ individual characters to pass;
+-- | @(take n)@ only allows @n@ individual characters to pass;
-- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass.
take :: (Monad m, Integral a) => a -> Pipe Text Text m ()
take n0 = go n0 where
go n
| n <= 0 = return ()
- | otherwise = do
+ | otherwise = do
txt <- await
let len = fromIntegral (T.length txt)
if (len > n)
go (n - len)
{-# INLINABLE take #-}
--- | @(drop n)@ drops the first @n@ characters
-drop :: (Monad m, Integral a) => a -> Pipe Text Text m r
-drop n0 = go n0 where
- go n
- | n <= 0 = cat
- | otherwise = do
- txt <- await
- let len = fromIntegral (T.length txt)
- if (len >= n)
- then do
- yield (T.drop (fromIntegral n) txt)
- cat
- else go (n - len)
-{-# INLINABLE drop #-}
-
-- | Take characters until they fail the predicate
takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m ()
takeWhile predicate = go
else yield prefix
{-# INLINABLE takeWhile #-}
--- | Drop characters until they fail the predicate
-dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r
-dropWhile predicate = go where
- go = do
- txt <- await
- case T.findIndex (not . predicate) txt of
- Nothing -> go
- Just i -> do
- yield (T.drop i txt)
- cat
-{-# INLINABLE dropWhile #-}
-
-- | Only allows 'Char's to pass if they satisfy the predicate
filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r
filter predicate = P.map (T.filter predicate)
{-# INLINABLE filter #-}
-{-# RULES "p >-> filter q" forall p q .
- p >-> filter q = for p (\txt -> yield (T.filter q txt))
- #-}
-
-- | Strict left scan over the characters
+-- >>> let margaret = ["Margaret, are you grieving\nOver Golde","ngrove unleaving?":: Text]
+-- >>> let title_caser a x = case a of ' ' -> Data.Char.toUpper x; _ -> x
+-- >>> toLazy $ each margaret >-> scan title_caser ' '
+-- " Margaret, Are You Grieving\nOver Goldengrove Unleaving?"
+
scan
:: (Monad m)
=> (Char -> Char -> Char) -> Char -> Pipe Text Text m r
go c'
{-# INLINABLE scan #-}
+-- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utilities,
+-- here acting as 'Text' pipes, rather as they would on a lazy text
+toCaseFold :: Monad m => Pipe Text Text m r
+toCaseFold = P.map T.toCaseFold
+{-# INLINEABLE toCaseFold #-}
+
+-- | lowercase incoming 'Text'
+toLower :: Monad m => Pipe Text Text m r
+toLower = P.map T.toLower
+{-# INLINEABLE toLower #-}
+
+-- | uppercase incoming 'Text'
+toUpper :: Monad m => Pipe Text Text m r
+toUpper = P.map T.toUpper
+{-# INLINEABLE toUpper #-}
+
+-- | Remove leading white space from an incoming succession of 'Text's
+stripStart :: Monad m => Pipe Text Text m r
+stripStart = do
+ chunk <- await
+ let text = T.stripStart chunk
+ if T.null text
+ then stripStart
+ else do yield text
+ cat
+{-# INLINEABLE stripStart #-}
+
{-| Fold a pure 'Producer' of strict 'Text's into a lazy
'TL.Text'
-}
foldChars step begin done = P.fold (T.foldl' step) begin done
{-# INLINABLE foldChars #-}
+
-- | Retrieve the first 'Char'
head :: (Monad m) => Producer Text m () -> m (Maybe Char)
head = go
index
:: (Monad m, Integral a)
=> a-> Producer Text m () -> m (Maybe Char)
-index n p = head (p >-> drop n)
+index n p = head (drop n p)
{-# INLINABLE index #-}
--- | Store a tally of how many segments match the given 'Text'
-count :: (Monad m, Num n) => Text -> Producer Text m () -> m n
-count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c))
-{-# INLINABLE count #-}
-
-- | Consume the first character from a stream of 'Text'
---
+--
-- 'next' either fails with a 'Left' if the 'Producer' has no more characters or
-- succeeds with a 'Right' providing the next character and the remainder of the
-- 'Producer'.
Just _-> False )
{-# INLINABLE isEndOfChars #-}
-
-- | Splits a 'Producer' after the given number of characters
splitAt
:: (Monad m, Integral n)
Left r -> return (return r)
Right (txt, p') -> case T.uncons txt of
Nothing -> go p'
- Just (c, _) -> (yield txt >> p') ^. span (equals c)
+ Just (c, _) -> (yield txt >> p') ^. span (equals c)
{-# INLINABLE groupBy #-}
-- | Improper lens that splits after the first succession of identical 'Char' s
-group :: Monad m
+group :: Monad m
=> Lens' (Producer Text m r)
(Producer Text m (Producer Text m r))
group = groupBy (==)
{-| Improper lens that splits a 'Producer' after the first word
- Unlike 'words', this does not drop leading whitespace
+ Unlike 'words', this does not drop leading whitespace
-}
-word :: (Monad m)
+word :: (Monad m)
=> Lens' (Producer Text m r)
(Producer Text m (Producer Text m r))
word k p0 = fmap join (k (to p0))
p'^.break isSpace
{-# INLINABLE word #-}
-
-line :: (Monad m)
+line :: (Monad m)
=> Lens' (Producer Text m r)
(Producer Text m (Producer Text m r))
line = break (== '\n')
-
{-# INLINABLE line #-}
+-- | @(drop n)@ drops the first @n@ characters
+drop :: (Monad m, Integral n)
+ => n -> Producer Text m r -> Producer Text m r
+drop n p = do
+ p' <- lift $ runEffect (for (p ^. splitAt n) discard)
+ p'
+{-# INLINABLE drop #-}
+
+-- | Drop characters until they fail the predicate
+dropWhile :: (Monad m)
+ => (Char -> Bool) -> Producer Text m r -> Producer Text m r
+dropWhile predicate p = do
+ p' <- lift $ runEffect (for (p ^. span predicate) discard)
+ p'
+{-# INLINABLE dropWhile #-}
-- | Intersperse a 'Char' in between the characters of stream of 'Text'
intersperse
{-# INLINABLE intersperse #-}
+-- | Improper lens from unpacked 'Word8's to packaged 'ByteString's
+pack :: Monad m => Lens' (Producer Char m r) (Producer Text m r)
+pack k p = fmap _unpack (k (_pack p))
+{-# INLINABLE pack #-}
--- | Improper isomorphism between a 'Producer' of 'ByteString's and 'Word8's
-packChars :: Monad m => Iso' (Producer Char m x) (Producer Text m x)
-packChars = Data.Profunctor.dimap to (fmap from)
- where
- -- to :: Monad m => Producer Char m x -> Producer Text m x
- to p = PG.folds step id done (p^.PG.chunksOf defaultChunkSize)
+-- | Improper lens from packed 'ByteString's to unpacked 'Word8's
+unpack :: Monad m => Lens' (Producer Text m r) (Producer Char m r)
+unpack k p = fmap _pack (k (_unpack p))
+{-# INLINABLE unpack #-}
- step diffAs c = diffAs . (c:)
+_pack :: Monad m => Producer Char m r -> Producer Text m r
+_pack p = folds step id done (p^.PG.chunksOf defaultChunkSize)
+ where
+ step diffAs w8 = diffAs . (w8:)
done diffAs = T.pack (diffAs [])
+{-# INLINABLE _pack #-}
+
+_unpack :: Monad m => Producer Text m r -> Producer Char m r
+_unpack p = for p (each . T.unpack)
+{-# INLINABLE _unpack #-}
- -- from :: Monad m => Producer Text m x -> Producer Char m x
- from p = for p (each . T.unpack)
-{-# INLINABLE packChars #-}
+defaultChunkSize :: Int
+defaultChunkSize = 16384 - (sizeOf (undefined :: Int) `shiftL` 1)
-- | Split a text stream into 'FreeT'-delimited text streams of fixed size
chunksOf
:: (Monad m, Integral n)
- => n -> Lens' (Producer Text m r)
+ => n -> Lens' (Producer Text m r)
(FreeT (Producer Text m) m r)
chunksOf n k p0 = fmap concats (k (FreeT (go p0)))
where
return $ case x of
Left r -> Pure r
Right (txt, p') -> Free $ do
- p'' <- (yield txt >> p') ^. splitAt n
+ p'' <- (yield txt >> p') ^. splitAt n
return $ FreeT (go p'')
{-# INLINABLE chunksOf #-}
splitsWith
:: (Monad m)
=> (Char -> Bool)
- -> Producer Text m r
- -> FreeT (Producer Text m) m r
+ -> Producer Text m r -> FreeT (Producer Text m) m r
splitsWith predicate p0 = FreeT (go0 p0)
where
go0 p = do
return $ case x of
Left r -> Pure r
Right (_, p') -> Free $ do
- p'' <- p' ^. span (not . predicate)
+ p'' <- p' ^. span (not . predicate)
return $ FreeT (go1 p'')
{-# INLINABLE splitsWith #-}
-> Lens' (Producer Text m r)
(FreeT (Producer Text m) m r)
splits c k p =
- fmap (PG.intercalates (yield (T.singleton c))) (k (splitsWith (c ==) p))
+ fmap (intercalates (yield (T.singleton c))) (k (splitsWith (c ==) p))
{-# INLINABLE splits #-}
{-| Isomorphism between a stream of 'Text' and groups of equivalent 'Char's , using the
:: Monad m
=> (Char -> Char -> Bool)
-> Lens' (Producer Text m x) (FreeT (Producer Text m) m x)
-groupsBy equals k p0 = fmap concats (k (FreeT (go p0))) where
+groupsBy equals k p0 = fmap concats (k (FreeT (go p0))) where
go p = do x <- next p
case x of Left r -> return (Pure r)
Right (bs, p') -> case T.uncons bs of
{-| Split a text stream into 'FreeT'-delimited lines
-}
lines
- :: (Monad m) => Iso' (Producer Text m r) (FreeT (Producer Text m) m r)
-lines = Data.Profunctor.dimap _lines (fmap _unlines)
- where
- _lines p0 = FreeT (go0 p0)
+ :: (Monad m) => Lens' (Producer Text m r) (FreeT (Producer Text m) m r)
+lines k p = fmap _unlines (k (_lines p))
+{-# INLINABLE lines #-}
+
+unlines
+ :: Monad m
+ => Lens' (FreeT (Producer Text m) m r) (Producer Text m r)
+unlines k p = fmap _lines (k (_unlines p))
+{-# INLINABLE unlines #-}
+
+_lines :: Monad m
+ => Producer Text m r -> FreeT (Producer Text m) m r
+_lines p0 = FreeT (go0 p0)
where
go0 p = do
x <- next p
case x of
Left r -> return $ Pure r
Right (_, p'') -> go0 p''
- -- _unlines
- -- :: Monad m
- -- => FreeT (Producer Text m) m x -> Producer Text m x
- _unlines = concats . PG.maps (<* yield (T.singleton '\n'))
-
-
-{-# INLINABLE lines #-}
+{-# INLINABLE _lines #-}
+_unlines :: Monad m
+ => FreeT (Producer Text m) m r -> Producer Text m r
+_unlines = concats . maps (<* yield (T.singleton '\n'))
+{-# INLINABLE _unlines #-}
--- | Split a text stream into 'FreeT'-delimited words
+-- | Split a text stream into 'FreeT'-delimited words. Note that
+-- roundtripping with e.g. @over words id@ eliminates extra space
+-- characters as with @Prelude.unwords . Prelude.words@
words
- :: (Monad m) => Iso' (Producer Text m r) (FreeT (Producer Text m) m r)
-words = Data.Profunctor.dimap go (fmap _unwords)
- where
- go p = FreeT $ do
- x <- next (p >-> dropWhile isSpace)
+ :: (Monad m) => Lens' (Producer Text m r) (FreeT (Producer Text m) m r)
+words k p = fmap _unwords (k (_words p))
+{-# INLINABLE words #-}
+
+unwords
+ :: Monad m
+ => Lens' (FreeT (Producer Text m) m r) (Producer Text m r)
+unwords k p = fmap _words (k (_unwords p))
+{-# INLINABLE unwords #-}
+
+_words :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r
+_words p = FreeT $ do
+ x <- next (dropWhile isSpace p)
return $ case x of
Left r -> Pure r
Right (bs, p') -> Free $ do
p'' <- (yield bs >> p') ^. break isSpace
- return (go p'')
- _unwords = PG.intercalates (yield $ T.singleton ' ')
-
-{-# INLINABLE words #-}
+ return (_words p'')
+{-# INLINABLE _words #-}
+
+_unwords :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r
+_unwords = intercalates (yield $ T.singleton ' ')
+{-# INLINABLE _unwords #-}
{-| 'intercalate' concatenates the 'FreeT'-delimited text streams after
-}
intercalate
:: (Monad m)
- => Producer Text m ()
- -> FreeT (Producer Text m) m r
- -> Producer Text m r
+ => Producer Text m () -> FreeT (Producer Text m) m r -> Producer Text m r
intercalate p0 = go0
where
go0 f = do
go1 f'
{-# INLINABLE intercalate #-}
-{-| Join 'FreeT'-delimited lines into a text stream
--}
-unlines
- :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r
-unlines = go
- where
- go f = do
- x <- lift (runFreeT f)
- case x of
- Pure r -> return r
- Free p -> do
- f' <- p
- yield $ T.singleton '\n'
- go f'
-{-# INLINABLE unlines #-}
-
-{-| Join 'FreeT'-delimited words into a text stream
--}
-unwords
- :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r
-unwords = intercalate (yield $ T.singleton ' ')
-{-# INLINABLE unwords #-}
{- $reexports
-
+
@Data.Text@ re-exports the 'Text' type.
- @Pipes.Parse@ re-exports 'input', 'concat', 'FreeT' (the type) and the 'Parse' synonym.
+ @Pipes.Parse@ re-exports 'input', 'concat', 'FreeT' (the type) and the 'Parse' synonym.
-}
+type Lens' a b = forall f . Functor f => (b -> f b) -> (a -> f a)
projects / github / fretlink / text-pipes.git / blobdiff