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31f41a5d | 1 | {-# LANGUAGE RankNTypes, TypeFamilies, CPP #-} |
91727d11 | 2 | |
13a43263 | 3 | {-| This module provides @pipes@ utilities for \"text streams\", which are |
31f41a5d | 4 | streams of 'Text' chunks. The individual chunks are uniformly @strict@, but |
5 | can interact lazy 'Text's and 'IO.Handle's. | |
91727d11 | 6 | |
7 | To stream to or from 'IO.Handle's, use 'fromHandle' or 'toHandle'. For | |
31f41a5d | 8 | example, the following program copies a document from one file to another: |
91727d11 | 9 | |
10 | > import Pipes | |
31f41a5d | 11 | > import qualified Data.Text.Pipes as Text |
91727d11 | 12 | > import System.IO |
13 | > | |
14 | > main = | |
15 | > withFile "inFile.txt" ReadMode $ \hIn -> | |
16 | > withFile "outFile.txt" WriteMode $ \hOut -> | |
31f41a5d | 17 | > runEffect $ Text.fromHandle hIn >-> Text.toHandle hOut |
18 | ||
19 | To stream from files, the following is perhaps more Prelude-like (note that it uses Pipes.Safe): | |
91727d11 | 20 | |
13a43263 | 21 | > import Pipes |
31f41a5d | 22 | > import qualified Data.Text.Pipes as Text |
13a43263 | 23 | > import Pipes.Safe |
24 | > | |
31f41a5d | 25 | > main = runSafeT $ runEffect $ Text.readFile "inFile.txt" >-> Text.writeFile "outFile.txt" |
13a43263 | 26 | |
91727d11 | 27 | You can stream to and from 'stdin' and 'stdout' using the predefined 'stdin' |
31f41a5d | 28 | and 'stdout' proxies, as with the following \"echo\" program: |
91727d11 | 29 | |
31f41a5d | 30 | > main = runEffect $ Text.stdin >-> Text.stdout |
91727d11 | 31 | |
32 | You can also translate pure lazy 'TL.Text's to and from proxies: | |
33 | ||
31f41a5d | 34 | > main = runEffect $ Text.fromLazy (TL.pack "Hello, world!\n") >-> Text.stdout |
91727d11 | 35 | |
36 | In addition, this module provides many functions equivalent to lazy | |
31f41a5d | 37 | 'Text' functions so that you can transform or fold text streams. For |
91727d11 | 38 | example, to stream only the first three lines of 'stdin' to 'stdout' you |
31f41a5d | 39 | might write: |
91727d11 | 40 | |
41 | > import Pipes | |
31f41a5d | 42 | > import qualified Pipes.Text as Text |
43 | > import qualified Pipes.Parse as Parse | |
91727d11 | 44 | > |
31f41a5d | 45 | > main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout |
91727d11 | 46 | > where |
31f41a5d | 47 | > takeLines n = Text.unlines . Parse.takeFree n . Text.lines |
91727d11 | 48 | |
31f41a5d | 49 | The above program will never bring more than one chunk of text (~ 32 KB) into |
91727d11 | 50 | memory, no matter how long the lines are. |
51 | ||
52 | Note that functions in this library are designed to operate on streams that | |
31f41a5d | 53 | are insensitive to text boundaries. This means that they may freely split |
54 | text into smaller texts and /discard empty texts/. However, they will | |
55 | /never concatenate texts/ in order to provide strict upper bounds on memory | |
91727d11 | 56 | usage. |
57 | -} | |
58 | ||
7faef8bc | 59 | module Pipes.Text ( |
91727d11 | 60 | -- * Producers |
61 | fromLazy, | |
62 | stdin, | |
63 | fromHandle, | |
64 | readFile, | |
65 | stdinLn, | |
91727d11 | 66 | |
67 | -- * Consumers | |
68 | stdout, | |
69 | stdoutLn, | |
70 | toHandle, | |
71 | writeFile, | |
72 | ||
73 | -- * Pipes | |
74 | map, | |
75 | concatMap, | |
76 | take, | |
77 | drop, | |
78 | takeWhile, | |
79 | dropWhile, | |
80 | filter, | |
91727d11 | 81 | scan, |
7faef8bc | 82 | encodeUtf8, |
83 | pack, | |
84 | unpack, | |
85 | stripStart, | |
91727d11 | 86 | |
87 | -- * Folds | |
88 | toLazy, | |
89 | toLazyM, | |
90 | fold, | |
91 | head, | |
92 | last, | |
93 | null, | |
94 | length, | |
95 | any, | |
96 | all, | |
97 | maximum, | |
98 | minimum, | |
91727d11 | 99 | find, |
100 | index, | |
101 | -- elemIndex, | |
102 | -- findIndex, | |
31f41a5d | 103 | count, |
91727d11 | 104 | |
105 | -- * Splitters | |
106 | splitAt, | |
107 | chunksOf, | |
108 | span, | |
109 | break, | |
110 | splitWith, | |
111 | split, | |
112 | groupBy, | |
113 | group, | |
114 | lines, | |
115 | words, | |
31f41a5d | 116 | #if MIN_VERSION_text(0,11,4) |
117 | decodeUtf8, | |
118 | #endif | |
91727d11 | 119 | -- * Transformations |
120 | intersperse, | |
31f41a5d | 121 | |
91727d11 | 122 | -- * Joiners |
123 | intercalate, | |
124 | unlines, | |
125 | unwords, | |
126 | ||
31f41a5d | 127 | -- * Character Parsers |
91727d11 | 128 | -- $parse |
31f41a5d | 129 | nextChar, |
130 | drawChar, | |
131 | unDrawChar, | |
132 | peekChar, | |
133 | isEndOfChars, | |
91727d11 | 134 | |
135 | -- * Re-exports | |
136 | -- $reexports | |
137 | module Data.Text, | |
91727d11 | 138 | module Pipes.Parse |
139 | ) where | |
140 | ||
141 | import Control.Exception (throwIO, try) | |
142 | import Control.Monad (liftM, unless) | |
143 | import Control.Monad.Trans.State.Strict (StateT) | |
144 | import qualified Data.Text as T | |
145 | import qualified Data.Text.IO as T | |
31f41a5d | 146 | import qualified Data.Text.Encoding as TE |
91727d11 | 147 | import Data.Text (Text) |
148 | import qualified Data.Text.Lazy as TL | |
149 | import qualified Data.Text.Lazy.IO as TL | |
150 | import Data.Text.Lazy.Internal (foldrChunks, defaultChunkSize) | |
151 | import Data.ByteString.Unsafe (unsafeTake, unsafeDrop) | |
31f41a5d | 152 | import Data.ByteString (ByteString) |
153 | import qualified Data.ByteString as B | |
91727d11 | 154 | import Data.Char (ord) |
155 | import Data.Functor.Identity (Identity) | |
156 | import qualified Data.List as List | |
157 | import Foreign.C.Error (Errno(Errno), ePIPE) | |
158 | import qualified GHC.IO.Exception as G | |
159 | import Pipes | |
160 | import qualified Pipes.ByteString.Parse as PBP | |
c0343bc9 | 161 | import Pipes.Text.Parse ( |
31f41a5d | 162 | nextChar, drawChar, unDrawChar, peekChar, isEndOfChars ) |
91727d11 | 163 | import Pipes.Core (respond, Server') |
164 | import qualified Pipes.Parse as PP | |
165 | import Pipes.Parse (input, concat, FreeT) | |
166 | import qualified Pipes.Safe.Prelude as Safe | |
167 | import qualified Pipes.Safe as Safe | |
168 | import Pipes.Safe (MonadSafe(..), Base(..)) | |
169 | import qualified Pipes.Prelude as P | |
170 | import qualified System.IO as IO | |
171 | import Data.Char (isSpace) | |
172 | import Prelude hiding ( | |
173 | all, | |
174 | any, | |
175 | break, | |
176 | concat, | |
177 | concatMap, | |
178 | drop, | |
179 | dropWhile, | |
180 | elem, | |
181 | filter, | |
182 | head, | |
183 | last, | |
184 | lines, | |
185 | length, | |
186 | map, | |
187 | maximum, | |
188 | minimum, | |
189 | notElem, | |
190 | null, | |
191 | readFile, | |
192 | span, | |
193 | splitAt, | |
194 | take, | |
195 | takeWhile, | |
196 | unlines, | |
197 | unwords, | |
198 | words, | |
199 | writeFile ) | |
200 | ||
201 | -- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's | |
202 | fromLazy :: (Monad m) => TL.Text -> Producer' Text m () | |
203 | fromLazy = foldrChunks (\e a -> yield e >> a) (return ()) | |
204 | {-# INLINABLE fromLazy #-} | |
205 | ||
206 | -- | Stream bytes from 'stdin' | |
207 | stdin :: MonadIO m => Producer' Text m () | |
208 | stdin = fromHandle IO.stdin | |
209 | {-# INLINABLE stdin #-} | |
210 | ||
31f41a5d | 211 | {-| Convert a 'IO.Handle' into a text stream using a text size |
212 | determined by the good sense of the text library. | |
213 | ||
214 | -} | |
215 | ||
91727d11 | 216 | fromHandle :: MonadIO m => IO.Handle -> Producer' Text m () |
217 | fromHandle h = go where | |
218 | go = do txt <- liftIO (T.hGetChunk h) | |
219 | unless (T.null txt) $ do yield txt | |
220 | go | |
221 | {-# INLINABLE fromHandle#-} | |
222 | ||
6f6f9974 | 223 | {-| Stream text from a file using Pipes.Safe |
224 | ||
31f41a5d | 225 | >>> runSafeT $ runEffect $ Text.readFile "hello.hs" >-> Text.map toUpper >-> hoist lift Text.stdout |
226 | MAIN = PUTSTRLN "HELLO WORLD" | |
6f6f9974 | 227 | -} |
228 | ||
91727d11 | 229 | readFile :: (MonadSafe m, Base m ~ IO) => FilePath -> Producer' Text m () |
230 | readFile file = Safe.withFile file IO.ReadMode fromHandle | |
231 | {-# INLINABLE readFile #-} | |
232 | ||
31f41a5d | 233 | {-| Stream lines of text from stdin (for testing in ghci etc.) |
234 | ||
235 | >>> let safely = runSafeT . runEffect | |
236 | >>> safely $ for Text.stdinLn (lift . lift . print . T.length) | |
237 | hello | |
238 | 5 | |
239 | world | |
240 | 5 | |
241 | ||
242 | -} | |
91727d11 | 243 | stdinLn :: MonadIO m => Producer' Text m () |
31f41a5d | 244 | stdinLn = go where |
91727d11 | 245 | go = do |
246 | eof <- liftIO (IO.hIsEOF IO.stdin) | |
247 | unless eof $ do | |
248 | txt <- liftIO (T.hGetLine IO.stdin) | |
249 | yield txt | |
250 | go | |
251 | ||
91727d11 | 252 | |
31f41a5d | 253 | {-| Stream text to 'stdout' |
91727d11 | 254 | |
255 | Unlike 'toHandle', 'stdout' gracefully terminates on a broken output pipe. | |
256 | ||
257 | Note: For best performance, use @(for source (liftIO . putStr))@ instead of | |
31f41a5d | 258 | @(source >-> stdout)@ in suitable cases. |
91727d11 | 259 | -} |
260 | stdout :: MonadIO m => Consumer' Text m () | |
261 | stdout = go | |
262 | where | |
263 | go = do | |
264 | txt <- await | |
265 | x <- liftIO $ try (T.putStr txt) | |
266 | case x of | |
267 | Left (G.IOError { G.ioe_type = G.ResourceVanished | |
268 | , G.ioe_errno = Just ioe }) | |
269 | | Errno ioe == ePIPE | |
270 | -> return () | |
271 | Left e -> liftIO (throwIO e) | |
272 | Right () -> go | |
273 | {-# INLINABLE stdout #-} | |
274 | ||
275 | stdoutLn :: (MonadIO m) => Consumer' Text m () | |
276 | stdoutLn = go | |
277 | where | |
278 | go = do | |
279 | str <- await | |
280 | x <- liftIO $ try (T.putStrLn str) | |
281 | case x of | |
282 | Left (G.IOError { G.ioe_type = G.ResourceVanished | |
283 | , G.ioe_errno = Just ioe }) | |
284 | | Errno ioe == ePIPE | |
285 | -> return () | |
286 | Left e -> liftIO (throwIO e) | |
287 | Right () -> go | |
288 | {-# INLINABLE stdoutLn #-} | |
289 | ||
31f41a5d | 290 | {-| Convert a text stream into a 'Handle' |
91727d11 | 291 | |
31f41a5d | 292 | Note: again, for best performance, where possible use |
293 | @(for source (liftIO . hPutStr handle))@ instead of @(source >-> toHandle handle)@. | |
91727d11 | 294 | -} |
295 | toHandle :: MonadIO m => IO.Handle -> Consumer' Text m r | |
296 | toHandle h = for cat (liftIO . T.hPutStr h) | |
297 | {-# INLINABLE toHandle #-} | |
298 | ||
31f41a5d | 299 | -- | Stream text into a file. Uses @pipes-safe@. |
91727d11 | 300 | writeFile :: (MonadSafe m, Base m ~ IO) => FilePath -> Consumer' Text m () |
301 | writeFile file = Safe.withFile file IO.WriteMode toHandle | |
302 | ||
303 | -- | Apply a transformation to each 'Char' in the stream | |
304 | map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r | |
305 | map f = P.map (T.map f) | |
306 | {-# INLINABLE map #-} | |
307 | ||
31f41a5d | 308 | -- | Map a function over the characters of a text stream and concatenate the results |
91727d11 | 309 | concatMap |
310 | :: (Monad m) => (Char -> Text) -> Pipe Text Text m r | |
311 | concatMap f = P.map (T.concatMap f) | |
312 | {-# INLINABLE concatMap #-} | |
313 | ||
7faef8bc | 314 | |
315 | -- | Transform a Pipe of 'Text' into a Pipe of 'ByteString's using UTF-8 | |
316 | -- encoding | |
317 | encodeUtf8 :: Monad m => Pipe Text ByteString m r | |
318 | encodeUtf8 = P.map TE.encodeUtf8 | |
319 | {-# INLINEABLE encodeUtf8 #-} | |
320 | ||
c0343bc9 | 321 | -- | Transform a Pipe of 'String's into one of 'Text' chunks |
7faef8bc | 322 | pack :: Monad m => Pipe String Text m r |
323 | pack = P.map T.pack | |
324 | {-# INLINEABLE pack #-} | |
325 | ||
c0343bc9 | 326 | -- | Transforma a Pipes of 'Text' chunks into one of 'String's |
7faef8bc | 327 | unpack :: Monad m => Pipe Text String m r |
328 | unpack = P.map T.unpack | |
329 | {-# INLINEABLE unpack #-} | |
330 | ||
c0343bc9 | 331 | -- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utility, |
7faef8bc | 332 | -- here acting on a 'Text' pipe, rather as they would on a lazy text |
333 | toCaseFold :: Monad m => Pipe Text Text m () | |
334 | toCaseFold = P.map T.toCaseFold | |
335 | {-# INLINEABLE toCaseFold #-} | |
336 | ||
c0343bc9 | 337 | -- | lowercase incoming 'Text' |
7faef8bc | 338 | toLower :: Monad m => Pipe Text Text m () |
339 | toLower = P.map T.toLower | |
340 | {-# INLINEABLE toLower #-} | |
341 | ||
c0343bc9 | 342 | -- | uppercase incoming 'Text' |
7faef8bc | 343 | toUpper :: Monad m => Pipe Text Text m () |
344 | toUpper = P.map T.toUpper | |
345 | {-# INLINEABLE toUpper #-} | |
346 | ||
c0343bc9 | 347 | -- | Remove leading white space from an incoming succession of 'Text's |
7faef8bc | 348 | stripStart :: Monad m => Pipe Text Text m r |
349 | stripStart = do | |
350 | chunk <- await | |
351 | let text = T.stripStart chunk | |
352 | if T.null text | |
353 | then stripStart | |
354 | else cat | |
355 | {-# INLINEABLE stripStart #-} | |
356 | ||
31f41a5d | 357 | -- | @(take n)@ only allows @n@ individual characters to pass; |
358 | -- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass. | |
91727d11 | 359 | take :: (Monad m, Integral a) => a -> Pipe Text Text m () |
360 | take n0 = go n0 where | |
361 | go n | |
362 | | n <= 0 = return () | |
363 | | otherwise = do | |
31f41a5d | 364 | txt <- await |
365 | let len = fromIntegral (T.length txt) | |
91727d11 | 366 | if (len > n) |
31f41a5d | 367 | then yield (T.take (fromIntegral n) txt) |
91727d11 | 368 | else do |
31f41a5d | 369 | yield txt |
91727d11 | 370 | go (n - len) |
371 | {-# INLINABLE take #-} | |
372 | ||
31f41a5d | 373 | -- | @(drop n)@ drops the first @n@ characters |
91727d11 | 374 | drop :: (Monad m, Integral a) => a -> Pipe Text Text m r |
375 | drop n0 = go n0 where | |
376 | go n | |
377 | | n <= 0 = cat | |
378 | | otherwise = do | |
31f41a5d | 379 | txt <- await |
380 | let len = fromIntegral (T.length txt) | |
91727d11 | 381 | if (len >= n) |
382 | then do | |
31f41a5d | 383 | yield (T.drop (fromIntegral n) txt) |
91727d11 | 384 | cat |
385 | else go (n - len) | |
386 | {-# INLINABLE drop #-} | |
387 | ||
31f41a5d | 388 | -- | Take characters until they fail the predicate |
91727d11 | 389 | takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m () |
390 | takeWhile predicate = go | |
391 | where | |
392 | go = do | |
31f41a5d | 393 | txt <- await |
394 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 395 | if (T.null suffix) |
396 | then do | |
31f41a5d | 397 | yield txt |
91727d11 | 398 | go |
399 | else yield prefix | |
400 | {-# INLINABLE takeWhile #-} | |
401 | ||
31f41a5d | 402 | -- | Drop characters until they fail the predicate |
91727d11 | 403 | dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r |
404 | dropWhile predicate = go where | |
405 | go = do | |
31f41a5d | 406 | txt <- await |
407 | case T.findIndex (not . predicate) txt of | |
91727d11 | 408 | Nothing -> go |
409 | Just i -> do | |
31f41a5d | 410 | yield (T.drop i txt) |
91727d11 | 411 | cat |
412 | {-# INLINABLE dropWhile #-} | |
413 | ||
414 | -- | Only allows 'Char's to pass if they satisfy the predicate | |
415 | filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r | |
416 | filter predicate = P.map (T.filter predicate) | |
417 | {-# INLINABLE filter #-} | |
418 | ||
31f41a5d | 419 | |
420 | -- | Strict left scan over the characters | |
91727d11 | 421 | scan |
422 | :: (Monad m) | |
423 | => (Char -> Char -> Char) -> Char -> Pipe Text Text m r | |
424 | scan step begin = go begin | |
425 | where | |
31f41a5d | 426 | go c = do |
427 | txt <- await | |
428 | let txt' = T.scanl step c txt | |
429 | c' = T.last txt' | |
430 | yield txt' | |
431 | go c' | |
91727d11 | 432 | {-# INLINABLE scan #-} |
433 | ||
434 | {-| Fold a pure 'Producer' of strict 'Text's into a lazy | |
435 | 'TL.Text' | |
436 | -} | |
437 | toLazy :: Producer Text Identity () -> TL.Text | |
438 | toLazy = TL.fromChunks . P.toList | |
439 | {-# INLINABLE toLazy #-} | |
440 | ||
441 | {-| Fold an effectful 'Producer' of strict 'Text's into a lazy | |
442 | 'TL.Text' | |
443 | ||
444 | Note: 'toLazyM' is not an idiomatic use of @pipes@, but I provide it for | |
445 | simple testing purposes. Idiomatic @pipes@ style consumes the chunks | |
446 | immediately as they are generated instead of loading them all into memory. | |
447 | -} | |
448 | toLazyM :: (Monad m) => Producer Text m () -> m TL.Text | |
449 | toLazyM = liftM TL.fromChunks . P.toListM | |
450 | {-# INLINABLE toLazyM #-} | |
451 | ||
31f41a5d | 452 | -- | Reduce the text stream using a strict left fold over characters |
91727d11 | 453 | fold |
454 | :: Monad m | |
455 | => (x -> Char -> x) -> x -> (x -> r) -> Producer Text m () -> m r | |
31f41a5d | 456 | fold step begin done = P.fold (T.foldl' step) begin done |
91727d11 | 457 | {-# INLINABLE fold #-} |
458 | ||
459 | -- | Retrieve the first 'Char' | |
460 | head :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
461 | head = go | |
462 | where | |
463 | go p = do | |
464 | x <- nextChar p | |
465 | case x of | |
466 | Left _ -> return Nothing | |
31f41a5d | 467 | Right (c, _) -> return (Just c) |
91727d11 | 468 | {-# INLINABLE head #-} |
469 | ||
470 | -- | Retrieve the last 'Char' | |
471 | last :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
472 | last = go Nothing | |
473 | where | |
474 | go r p = do | |
475 | x <- next p | |
476 | case x of | |
477 | Left () -> return r | |
31f41a5d | 478 | Right (txt, p') -> |
479 | if (T.null txt) | |
91727d11 | 480 | then go r p' |
31f41a5d | 481 | else go (Just $ T.last txt) p' |
91727d11 | 482 | {-# INLINABLE last #-} |
483 | ||
484 | -- | Determine if the stream is empty | |
485 | null :: (Monad m) => Producer Text m () -> m Bool | |
486 | null = P.all T.null | |
487 | {-# INLINABLE null #-} | |
488 | ||
489 | -- | Count the number of bytes | |
490 | length :: (Monad m, Num n) => Producer Text m () -> m n | |
31f41a5d | 491 | length = P.fold (\n txt -> n + fromIntegral (T.length txt)) 0 id |
91727d11 | 492 | {-# INLINABLE length #-} |
493 | ||
494 | -- | Fold that returns whether 'M.Any' received 'Char's satisfy the predicate | |
495 | any :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
496 | any predicate = P.any (T.any predicate) | |
497 | {-# INLINABLE any #-} | |
498 | ||
499 | -- | Fold that returns whether 'M.All' received 'Char's satisfy the predicate | |
500 | all :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
501 | all predicate = P.all (T.all predicate) | |
502 | {-# INLINABLE all #-} | |
503 | ||
504 | -- | Return the maximum 'Char' within a byte stream | |
505 | maximum :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
506 | maximum = P.fold step Nothing id | |
507 | where | |
31f41a5d | 508 | step mc txt = |
509 | if (T.null txt) | |
510 | then mc | |
511 | else Just $ case mc of | |
512 | Nothing -> T.maximum txt | |
513 | Just c -> max c (T.maximum txt) | |
91727d11 | 514 | {-# INLINABLE maximum #-} |
515 | ||
516 | -- | Return the minimum 'Char' within a byte stream | |
517 | minimum :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
518 | minimum = P.fold step Nothing id | |
519 | where | |
31f41a5d | 520 | step mc txt = |
521 | if (T.null txt) | |
522 | then mc | |
523 | else case mc of | |
524 | Nothing -> Just (T.minimum txt) | |
525 | Just c -> Just (min c (T.minimum txt)) | |
91727d11 | 526 | {-# INLINABLE minimum #-} |
527 | ||
91727d11 | 528 | -- | Find the first element in the stream that matches the predicate |
529 | find | |
530 | :: (Monad m) | |
531 | => (Char -> Bool) -> Producer Text m () -> m (Maybe Char) | |
532 | find predicate p = head (p >-> filter predicate) | |
533 | {-# INLINABLE find #-} | |
534 | ||
535 | -- | Index into a byte stream | |
536 | index | |
537 | :: (Monad m, Integral a) | |
538 | => a-> Producer Text m () -> m (Maybe Char) | |
539 | index n p = head (p >-> drop n) | |
540 | {-# INLINABLE index #-} | |
541 | ||
542 | -- | Find the index of an element that matches the given 'Char' | |
543 | -- elemIndex | |
544 | -- :: (Monad m, Num n) => Char -> Producer Text m () -> m (Maybe n) | |
545 | -- elemIndex w8 = findIndex (w8 ==) | |
546 | -- {-# INLINABLE elemIndex #-} | |
547 | ||
548 | -- | Store the first index of an element that satisfies the predicate | |
549 | -- findIndex | |
550 | -- :: (Monad m, Num n) | |
551 | -- => (Char -> Bool) -> Producer Text m () -> m (Maybe n) | |
552 | -- findIndex predicate p = P.head (p >-> findIndices predicate) | |
553 | -- {-# INLINABLE findIndex #-} | |
554 | -- | |
31f41a5d | 555 | -- | Store a tally of how many segments match the given 'Text' |
556 | count :: (Monad m, Num n) => Text -> Producer Text m () -> m n | |
557 | count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c)) | |
558 | {-# INLINABLE count #-} | |
559 | ||
560 | #if MIN_VERSION_text(0,11,4) | |
561 | -- | Transform a Pipe of 'ByteString's expected to be UTF-8 encoded | |
562 | -- into a Pipe of Text | |
563 | decodeUtf8 | |
564 | :: Monad m | |
565 | => Producer ByteString m r -> Producer Text m (Producer ByteString m r) | |
566 | decodeUtf8 = go TE.streamDecodeUtf8 | |
567 | where go dec p = do | |
568 | x <- lift (next p) | |
569 | case x of | |
570 | Left r -> return (return r) | |
571 | Right (chunk, p') -> do | |
572 | let TE.Some text l dec' = dec chunk | |
573 | if B.null l | |
574 | then do | |
575 | yield text | |
576 | go dec' p' | |
577 | else return $ do | |
578 | yield l | |
579 | p' | |
580 | {-# INLINEABLE decodeUtf8 #-} | |
581 | #endif | |
582 | ||
583 | -- | Splits a 'Producer' after the given number of characters | |
91727d11 | 584 | splitAt |
585 | :: (Monad m, Integral n) | |
586 | => n | |
587 | -> Producer Text m r | |
588 | -> Producer' Text m (Producer Text m r) | |
589 | splitAt = go | |
590 | where | |
591 | go 0 p = return p | |
592 | go n p = do | |
593 | x <- lift (next p) | |
594 | case x of | |
595 | Left r -> return (return r) | |
31f41a5d | 596 | Right (txt, p') -> do |
597 | let len = fromIntegral (T.length txt) | |
91727d11 | 598 | if (len <= n) |
599 | then do | |
31f41a5d | 600 | yield txt |
91727d11 | 601 | go (n - len) p' |
602 | else do | |
31f41a5d | 603 | let (prefix, suffix) = T.splitAt (fromIntegral n) txt |
91727d11 | 604 | yield prefix |
605 | return (yield suffix >> p') | |
606 | {-# INLINABLE splitAt #-} | |
607 | ||
31f41a5d | 608 | -- | Split a text stream into 'FreeT'-delimited text streams of fixed size |
91727d11 | 609 | chunksOf |
610 | :: (Monad m, Integral n) | |
611 | => n -> Producer Text m r -> FreeT (Producer Text m) m r | |
612 | chunksOf n p0 = PP.FreeT (go p0) | |
613 | where | |
614 | go p = do | |
615 | x <- next p | |
616 | return $ case x of | |
617 | Left r -> PP.Pure r | |
31f41a5d | 618 | Right (txt, p') -> PP.Free $ do |
619 | p'' <- splitAt n (yield txt >> p') | |
91727d11 | 620 | return $ PP.FreeT (go p'') |
621 | {-# INLINABLE chunksOf #-} | |
622 | ||
31f41a5d | 623 | {-| Split a text stream in two, where the first text stream is the longest |
624 | consecutive group of text that satisfy the predicate | |
91727d11 | 625 | -} |
626 | span | |
627 | :: (Monad m) | |
628 | => (Char -> Bool) | |
629 | -> Producer Text m r | |
630 | -> Producer' Text m (Producer Text m r) | |
631 | span predicate = go | |
632 | where | |
633 | go p = do | |
634 | x <- lift (next p) | |
635 | case x of | |
636 | Left r -> return (return r) | |
31f41a5d | 637 | Right (txt, p') -> do |
638 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 639 | if (T.null suffix) |
640 | then do | |
31f41a5d | 641 | yield txt |
91727d11 | 642 | go p' |
643 | else do | |
644 | yield prefix | |
645 | return (yield suffix >> p') | |
646 | {-# INLINABLE span #-} | |
647 | ||
648 | {-| Split a byte stream in two, where the first byte stream is the longest | |
649 | consecutive group of bytes that don't satisfy the predicate | |
650 | -} | |
651 | break | |
652 | :: (Monad m) | |
653 | => (Char -> Bool) | |
654 | -> Producer Text m r | |
655 | -> Producer Text m (Producer Text m r) | |
656 | break predicate = span (not . predicate) | |
657 | {-# INLINABLE break #-} | |
658 | ||
659 | {-| Split a byte stream into sub-streams delimited by bytes that satisfy the | |
660 | predicate | |
661 | -} | |
662 | splitWith | |
663 | :: (Monad m) | |
664 | => (Char -> Bool) | |
665 | -> Producer Text m r | |
666 | -> PP.FreeT (Producer Text m) m r | |
667 | splitWith predicate p0 = PP.FreeT (go0 p0) | |
668 | where | |
669 | go0 p = do | |
670 | x <- next p | |
671 | case x of | |
672 | Left r -> return (PP.Pure r) | |
31f41a5d | 673 | Right (txt, p') -> |
674 | if (T.null txt) | |
91727d11 | 675 | then go0 p' |
676 | else return $ PP.Free $ do | |
31f41a5d | 677 | p'' <- span (not . predicate) (yield txt >> p') |
91727d11 | 678 | return $ PP.FreeT (go1 p'') |
679 | go1 p = do | |
680 | x <- nextChar p | |
681 | return $ case x of | |
682 | Left r -> PP.Pure r | |
683 | Right (_, p') -> PP.Free $ do | |
684 | p'' <- span (not . predicate) p' | |
685 | return $ PP.FreeT (go1 p'') | |
686 | {-# INLINABLE splitWith #-} | |
687 | ||
31f41a5d | 688 | -- | Split a text stream using the given 'Char' as the delimiter |
91727d11 | 689 | split :: (Monad m) |
690 | => Char | |
691 | -> Producer Text m r | |
692 | -> FreeT (Producer Text m) m r | |
31f41a5d | 693 | split c = splitWith (c ==) |
91727d11 | 694 | {-# INLINABLE split #-} |
695 | ||
31f41a5d | 696 | {-| Group a text stream into 'FreeT'-delimited byte streams using the supplied |
91727d11 | 697 | equality predicate |
698 | -} | |
699 | groupBy | |
700 | :: (Monad m) | |
701 | => (Char -> Char -> Bool) | |
702 | -> Producer Text m r | |
703 | -> FreeT (Producer Text m) m r | |
704 | groupBy equal p0 = PP.FreeT (go p0) | |
705 | where | |
706 | go p = do | |
707 | x <- next p | |
708 | case x of | |
709 | Left r -> return (PP.Pure r) | |
31f41a5d | 710 | Right (txt, p') -> case (T.uncons txt) of |
91727d11 | 711 | Nothing -> go p' |
31f41a5d | 712 | Just (c, _) -> do |
91727d11 | 713 | return $ PP.Free $ do |
31f41a5d | 714 | p'' <- span (equal c) (yield txt >> p') |
91727d11 | 715 | return $ PP.FreeT (go p'') |
716 | {-# INLINABLE groupBy #-} | |
717 | ||
718 | -- | Group a byte stream into 'FreeT'-delimited byte streams of identical bytes | |
719 | group | |
720 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
721 | group = groupBy (==) | |
722 | {-# INLINABLE group #-} | |
723 | ||
724 | {-| Split a byte stream into 'FreeT'-delimited lines | |
725 | ||
726 | Note: This function is purely for demonstration purposes since it assumes a | |
727 | particular encoding. You should prefer the 'Data.Text.Text' equivalent of | |
728 | this function from the upcoming @pipes-text@ library. | |
729 | -} | |
730 | lines | |
731 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
732 | lines p0 = PP.FreeT (go0 p0) | |
733 | where | |
734 | go0 p = do | |
735 | x <- next p | |
736 | case x of | |
737 | Left r -> return (PP.Pure r) | |
31f41a5d | 738 | Right (txt, p') -> |
739 | if (T.null txt) | |
91727d11 | 740 | then go0 p' |
31f41a5d | 741 | else return $ PP.Free $ go1 (yield txt >> p') |
91727d11 | 742 | go1 p = do |
743 | p' <- break ('\n' ==) p | |
744 | return $ PP.FreeT (go2 p') | |
745 | go2 p = do | |
746 | x <- nextChar p | |
747 | return $ case x of | |
748 | Left r -> PP.Pure r | |
749 | Right (_, p') -> PP.Free (go1 p') | |
750 | {-# INLINABLE lines #-} | |
91727d11 | 751 | |
31f41a5d | 752 | |
753 | ||
754 | -- | Split a text stream into 'FreeT'-delimited words | |
91727d11 | 755 | words |
756 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
757 | words p0 = removeEmpty (splitWith isSpace p0) | |
758 | where | |
759 | removeEmpty f = PP.FreeT $ do | |
760 | x <- PP.runFreeT f | |
761 | case x of | |
762 | PP.Pure r -> return (PP.Pure r) | |
763 | PP.Free p -> do | |
764 | y <- next p | |
765 | case y of | |
766 | Left f' -> PP.runFreeT (removeEmpty f') | |
767 | Right (bs, p') -> return $ PP.Free $ do | |
768 | yield bs | |
769 | f' <- p' | |
770 | return (removeEmpty f') | |
771 | {-# INLINABLE words #-} | |
772 | ||
773 | -- | Intersperse a 'Char' in between the bytes of the byte stream | |
774 | intersperse | |
775 | :: (Monad m) => Char -> Producer Text m r -> Producer Text m r | |
31f41a5d | 776 | intersperse c = go0 |
91727d11 | 777 | where |
778 | go0 p = do | |
779 | x <- lift (next p) | |
780 | case x of | |
781 | Left r -> return r | |
31f41a5d | 782 | Right (txt, p') -> do |
783 | yield (T.intersperse c txt) | |
91727d11 | 784 | go1 p' |
785 | go1 p = do | |
786 | x <- lift (next p) | |
787 | case x of | |
788 | Left r -> return r | |
31f41a5d | 789 | Right (txt, p') -> do |
790 | yield (T.singleton c) | |
791 | yield (T.intersperse c txt) | |
91727d11 | 792 | go1 p' |
793 | {-# INLINABLE intersperse #-} | |
794 | ||
31f41a5d | 795 | {-| 'intercalate' concatenates the 'FreeT'-delimited text streams after |
796 | interspersing a text stream in between them | |
91727d11 | 797 | -} |
798 | intercalate | |
799 | :: (Monad m) | |
800 | => Producer Text m () | |
801 | -> FreeT (Producer Text m) m r | |
802 | -> Producer Text m r | |
803 | intercalate p0 = go0 | |
804 | where | |
805 | go0 f = do | |
806 | x <- lift (PP.runFreeT f) | |
807 | case x of | |
808 | PP.Pure r -> return r | |
809 | PP.Free p -> do | |
810 | f' <- p | |
811 | go1 f' | |
812 | go1 f = do | |
813 | x <- lift (PP.runFreeT f) | |
814 | case x of | |
815 | PP.Pure r -> return r | |
816 | PP.Free p -> do | |
817 | p0 | |
818 | f' <- p | |
819 | go1 f' | |
820 | {-# INLINABLE intercalate #-} | |
821 | ||
822 | {-| Join 'FreeT'-delimited lines into a byte stream | |
91727d11 | 823 | -} |
824 | unlines | |
825 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
826 | unlines = go | |
827 | where | |
828 | go f = do | |
829 | x <- lift (PP.runFreeT f) | |
830 | case x of | |
831 | PP.Pure r -> return r | |
832 | PP.Free p -> do | |
833 | f' <- p | |
834 | yield $ T.singleton '\n' | |
835 | go f' | |
836 | {-# INLINABLE unlines #-} | |
837 | ||
31f41a5d | 838 | {-| Join 'FreeT'-delimited words into a text stream |
91727d11 | 839 | -} |
840 | unwords | |
841 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
842 | unwords = intercalate (yield $ T.pack " ") | |
843 | {-# INLINABLE unwords #-} | |
844 | ||
845 | {- $parse | |
31f41a5d | 846 | The following parsing utilities are single-character analogs of the ones found |
847 | @pipes-parse@. | |
91727d11 | 848 | -} |
849 | ||
91727d11 | 850 | {- $reexports |
31f41a5d | 851 | @Pipes.Text.Parse@ re-exports 'nextChar', 'drawChar', 'unDrawChar', 'peekChar', and 'isEndOfChars'. |
91727d11 | 852 | |
853 | @Data.Text@ re-exports the 'Text' type. | |
854 | ||
91727d11 | 855 | @Pipes.Parse@ re-exports 'input', 'concat', and 'FreeT' (the type). |
856 | -} |