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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 |
63ea9ffd | 5 | a 'Producer' can be converted to and from lazy 'Text's; an 'IO.Handle' can |
6 | be associated with a 'Producer' or 'Consumer' according as it is read or written to. | |
91727d11 | 7 | |
63ea9ffd | 8 | To stream to or from 'IO.Handle's, one can use 'fromHandle' or 'toHandle'. For |
31f41a5d | 9 | example, the following program copies a document from one file to another: |
91727d11 | 10 | |
11 | > import Pipes | |
31f41a5d | 12 | > import qualified Data.Text.Pipes as Text |
91727d11 | 13 | > import System.IO |
14 | > | |
15 | > main = | |
16 | > withFile "inFile.txt" ReadMode $ \hIn -> | |
17 | > withFile "outFile.txt" WriteMode $ \hOut -> | |
31f41a5d | 18 | > runEffect $ Text.fromHandle hIn >-> Text.toHandle hOut |
19 | ||
20 | To stream from files, the following is perhaps more Prelude-like (note that it uses Pipes.Safe): | |
91727d11 | 21 | |
13a43263 | 22 | > import Pipes |
31f41a5d | 23 | > import qualified Data.Text.Pipes as Text |
13a43263 | 24 | > import Pipes.Safe |
25 | > | |
31f41a5d | 26 | > main = runSafeT $ runEffect $ Text.readFile "inFile.txt" >-> Text.writeFile "outFile.txt" |
13a43263 | 27 | |
91727d11 | 28 | You can stream to and from 'stdin' and 'stdout' using the predefined 'stdin' |
31f41a5d | 29 | and 'stdout' proxies, as with the following \"echo\" program: |
91727d11 | 30 | |
31f41a5d | 31 | > main = runEffect $ Text.stdin >-> Text.stdout |
91727d11 | 32 | |
33 | You can also translate pure lazy 'TL.Text's to and from proxies: | |
34 | ||
31f41a5d | 35 | > main = runEffect $ Text.fromLazy (TL.pack "Hello, world!\n") >-> Text.stdout |
91727d11 | 36 | |
37 | In addition, this module provides many functions equivalent to lazy | |
31f41a5d | 38 | 'Text' functions so that you can transform or fold text streams. For |
91727d11 | 39 | example, to stream only the first three lines of 'stdin' to 'stdout' you |
31f41a5d | 40 | might write: |
91727d11 | 41 | |
42 | > import Pipes | |
31f41a5d | 43 | > import qualified Pipes.Text as Text |
44 | > import qualified Pipes.Parse as Parse | |
91727d11 | 45 | > |
31f41a5d | 46 | > main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout |
91727d11 | 47 | > where |
31f41a5d | 48 | > takeLines n = Text.unlines . Parse.takeFree n . Text.lines |
91727d11 | 49 | |
31f41a5d | 50 | The above program will never bring more than one chunk of text (~ 32 KB) into |
91727d11 | 51 | memory, no matter how long the lines are. |
52 | ||
53 | Note that functions in this library are designed to operate on streams that | |
31f41a5d | 54 | are insensitive to text boundaries. This means that they may freely split |
55 | text into smaller texts and /discard empty texts/. However, they will | |
56 | /never concatenate texts/ in order to provide strict upper bounds on memory | |
91727d11 | 57 | usage. |
58 | -} | |
59 | ||
7faef8bc | 60 | module Pipes.Text ( |
91727d11 | 61 | -- * Producers |
62 | fromLazy, | |
63 | stdin, | |
64 | fromHandle, | |
65 | readFile, | |
66 | stdinLn, | |
91727d11 | 67 | |
68 | -- * Consumers | |
69 | stdout, | |
70 | stdoutLn, | |
71 | toHandle, | |
72 | writeFile, | |
73 | ||
74 | -- * Pipes | |
75 | map, | |
76 | concatMap, | |
77 | take, | |
78 | drop, | |
79 | takeWhile, | |
80 | dropWhile, | |
81 | filter, | |
91727d11 | 82 | scan, |
7faef8bc | 83 | encodeUtf8, |
a02a69ad | 84 | #if MIN_VERSION_text(0,11,4) |
85 | pipeDecodeUtf8, | |
86 | pipeDecodeUtf8With, | |
87 | #endif | |
7faef8bc | 88 | pack, |
89 | unpack, | |
1d2434b5 | 90 | toCaseFold, |
91 | toLower, | |
92 | toUpper, | |
7faef8bc | 93 | stripStart, |
91727d11 | 94 | |
95 | -- * Folds | |
96 | toLazy, | |
97 | toLazyM, | |
98 | fold, | |
99 | head, | |
100 | last, | |
101 | null, | |
102 | length, | |
103 | any, | |
104 | all, | |
105 | maximum, | |
106 | minimum, | |
91727d11 | 107 | find, |
108 | index, | |
31f41a5d | 109 | count, |
91727d11 | 110 | |
111 | -- * Splitters | |
112 | splitAt, | |
113 | chunksOf, | |
114 | span, | |
115 | break, | |
116 | splitWith, | |
117 | split, | |
118 | groupBy, | |
119 | group, | |
120 | lines, | |
121 | words, | |
31f41a5d | 122 | #if MIN_VERSION_text(0,11,4) |
123 | decodeUtf8, | |
63ea9ffd | 124 | decodeUtf8With, |
31f41a5d | 125 | #endif |
91727d11 | 126 | -- * Transformations |
127 | intersperse, | |
31f41a5d | 128 | |
91727d11 | 129 | -- * Joiners |
130 | intercalate, | |
131 | unlines, | |
132 | unwords, | |
133 | ||
31f41a5d | 134 | -- * Character Parsers |
91727d11 | 135 | -- $parse |
31f41a5d | 136 | nextChar, |
137 | drawChar, | |
138 | unDrawChar, | |
139 | peekChar, | |
140 | isEndOfChars, | |
91727d11 | 141 | |
142 | -- * Re-exports | |
143 | -- $reexports | |
144 | module Data.Text, | |
91727d11 | 145 | module Pipes.Parse |
146 | ) where | |
147 | ||
148 | import Control.Exception (throwIO, try) | |
149 | import Control.Monad (liftM, unless) | |
acc6868f | 150 | import Control.Monad.Trans.State.Strict (StateT(..)) |
91727d11 | 151 | import qualified Data.Text as T |
152 | import qualified Data.Text.IO as T | |
31f41a5d | 153 | import qualified Data.Text.Encoding as TE |
63ea9ffd | 154 | import qualified Data.Text.Encoding.Error as TE |
91727d11 | 155 | import Data.Text (Text) |
156 | import qualified Data.Text.Lazy as TL | |
157 | import qualified Data.Text.Lazy.IO as TL | |
158 | import Data.Text.Lazy.Internal (foldrChunks, defaultChunkSize) | |
159 | import Data.ByteString.Unsafe (unsafeTake, unsafeDrop) | |
31f41a5d | 160 | import Data.ByteString (ByteString) |
161 | import qualified Data.ByteString as B | |
cf10d6f1 | 162 | import Data.Char (ord, isSpace) |
91727d11 | 163 | import Data.Functor.Identity (Identity) |
164 | import qualified Data.List as List | |
165 | import Foreign.C.Error (Errno(Errno), ePIPE) | |
166 | import qualified GHC.IO.Exception as G | |
167 | import Pipes | |
5e3f5409 | 168 | import qualified Pipes.ByteString as PB |
91727d11 | 169 | import qualified Pipes.ByteString.Parse as PBP |
c0343bc9 | 170 | import Pipes.Text.Parse ( |
31f41a5d | 171 | nextChar, drawChar, unDrawChar, peekChar, isEndOfChars ) |
91727d11 | 172 | import Pipes.Core (respond, Server') |
173 | import qualified Pipes.Parse as PP | |
174 | import Pipes.Parse (input, concat, FreeT) | |
175 | import qualified Pipes.Safe.Prelude as Safe | |
176 | import qualified Pipes.Safe as Safe | |
177 | import Pipes.Safe (MonadSafe(..), Base(..)) | |
178 | import qualified Pipes.Prelude as P | |
179 | import qualified System.IO as IO | |
180 | import Data.Char (isSpace) | |
63ea9ffd | 181 | import Data.Word (Word8) |
91727d11 | 182 | import Prelude hiding ( |
183 | all, | |
184 | any, | |
185 | break, | |
186 | concat, | |
187 | concatMap, | |
188 | drop, | |
189 | dropWhile, | |
190 | elem, | |
191 | filter, | |
192 | head, | |
193 | last, | |
194 | lines, | |
195 | length, | |
196 | map, | |
197 | maximum, | |
198 | minimum, | |
199 | notElem, | |
200 | null, | |
201 | readFile, | |
202 | span, | |
203 | splitAt, | |
204 | take, | |
205 | takeWhile, | |
206 | unlines, | |
207 | unwords, | |
208 | words, | |
209 | writeFile ) | |
210 | ||
211 | -- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's | |
212 | fromLazy :: (Monad m) => TL.Text -> Producer' Text m () | |
213 | fromLazy = foldrChunks (\e a -> yield e >> a) (return ()) | |
214 | {-# INLINABLE fromLazy #-} | |
215 | ||
62e8521c | 216 | -- | Stream text from 'stdin' |
91727d11 | 217 | stdin :: MonadIO m => Producer' Text m () |
218 | stdin = fromHandle IO.stdin | |
219 | {-# INLINABLE stdin #-} | |
220 | ||
31f41a5d | 221 | {-| Convert a 'IO.Handle' into a text stream using a text size |
222 | determined by the good sense of the text library. | |
223 | ||
224 | -} | |
225 | ||
91727d11 | 226 | fromHandle :: MonadIO m => IO.Handle -> Producer' Text m () |
5e3f5409 | 227 | #if MIN_VERSION_text(0,11,4) |
228 | fromHandle h = PB.fromHandle h >-> pipeDecodeUtf8 | |
229 | {-# INLINABLE fromHandle#-} | |
230 | -- bytestring fromHandle + streamDecodeUtf8 is 3 times as fast as | |
231 | -- the dedicated Text IO function 'hGetChunk' ; | |
232 | -- this way "runEffect $ PT.fromHandle hIn >-> PT.toHandle hOut" | |
233 | -- runs the same as the conduit equivalent, only slightly slower | |
234 | -- than "runEffect $ PB.fromHandle hIn >-> PB.toHandle hOut" | |
235 | ||
236 | #else | |
91727d11 | 237 | fromHandle h = go where |
238 | go = do txt <- liftIO (T.hGetChunk h) | |
239 | unless (T.null txt) $ do yield txt | |
240 | go | |
241 | {-# INLINABLE fromHandle#-} | |
5e3f5409 | 242 | #endif |
6f6f9974 | 243 | {-| Stream text from a file using Pipes.Safe |
244 | ||
31f41a5d | 245 | >>> runSafeT $ runEffect $ Text.readFile "hello.hs" >-> Text.map toUpper >-> hoist lift Text.stdout |
246 | MAIN = PUTSTRLN "HELLO WORLD" | |
6f6f9974 | 247 | -} |
248 | ||
91727d11 | 249 | readFile :: (MonadSafe m, Base m ~ IO) => FilePath -> Producer' Text m () |
250 | readFile file = Safe.withFile file IO.ReadMode fromHandle | |
251 | {-# INLINABLE readFile #-} | |
252 | ||
31f41a5d | 253 | {-| Stream lines of text from stdin (for testing in ghci etc.) |
254 | ||
255 | >>> let safely = runSafeT . runEffect | |
256 | >>> safely $ for Text.stdinLn (lift . lift . print . T.length) | |
257 | hello | |
258 | 5 | |
259 | world | |
260 | 5 | |
261 | ||
262 | -} | |
91727d11 | 263 | stdinLn :: MonadIO m => Producer' Text m () |
31f41a5d | 264 | stdinLn = go where |
91727d11 | 265 | go = do |
266 | eof <- liftIO (IO.hIsEOF IO.stdin) | |
267 | unless eof $ do | |
268 | txt <- liftIO (T.hGetLine IO.stdin) | |
269 | yield txt | |
270 | go | |
271 | ||
91727d11 | 272 | |
31f41a5d | 273 | {-| Stream text to 'stdout' |
91727d11 | 274 | |
275 | Unlike 'toHandle', 'stdout' gracefully terminates on a broken output pipe. | |
276 | ||
277 | Note: For best performance, use @(for source (liftIO . putStr))@ instead of | |
31f41a5d | 278 | @(source >-> stdout)@ in suitable cases. |
91727d11 | 279 | -} |
280 | stdout :: MonadIO m => Consumer' Text m () | |
281 | stdout = go | |
282 | where | |
283 | go = do | |
284 | txt <- await | |
285 | x <- liftIO $ try (T.putStr txt) | |
286 | case x of | |
287 | Left (G.IOError { G.ioe_type = G.ResourceVanished | |
288 | , G.ioe_errno = Just ioe }) | |
289 | | Errno ioe == ePIPE | |
290 | -> return () | |
291 | Left e -> liftIO (throwIO e) | |
292 | Right () -> go | |
293 | {-# INLINABLE stdout #-} | |
294 | ||
295 | stdoutLn :: (MonadIO m) => Consumer' Text m () | |
296 | stdoutLn = go | |
297 | where | |
298 | go = do | |
299 | str <- await | |
300 | x <- liftIO $ try (T.putStrLn str) | |
301 | case x of | |
302 | Left (G.IOError { G.ioe_type = G.ResourceVanished | |
303 | , G.ioe_errno = Just ioe }) | |
304 | | Errno ioe == ePIPE | |
305 | -> return () | |
306 | Left e -> liftIO (throwIO e) | |
307 | Right () -> go | |
308 | {-# INLINABLE stdoutLn #-} | |
309 | ||
31f41a5d | 310 | {-| Convert a text stream into a 'Handle' |
91727d11 | 311 | |
31f41a5d | 312 | Note: again, for best performance, where possible use |
313 | @(for source (liftIO . hPutStr handle))@ instead of @(source >-> toHandle handle)@. | |
91727d11 | 314 | -} |
315 | toHandle :: MonadIO m => IO.Handle -> Consumer' Text m r | |
316 | toHandle h = for cat (liftIO . T.hPutStr h) | |
317 | {-# INLINABLE toHandle #-} | |
318 | ||
d4732515 | 319 | {-# RULES "p >-> toHandle h" forall p h . |
ff38b9f0 | 320 | p >-> toHandle h = for p (\txt -> liftIO (T.hPutStr h txt)) |
d4732515 | 321 | #-} |
322 | ||
323 | ||
31f41a5d | 324 | -- | Stream text into a file. Uses @pipes-safe@. |
91727d11 | 325 | writeFile :: (MonadSafe m, Base m ~ IO) => FilePath -> Consumer' Text m () |
326 | writeFile file = Safe.withFile file IO.WriteMode toHandle | |
327 | ||
328 | -- | Apply a transformation to each 'Char' in the stream | |
329 | map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r | |
330 | map f = P.map (T.map f) | |
331 | {-# INLINABLE map #-} | |
332 | ||
ff38b9f0 | 333 | {-# RULES "p >-> map f" forall p f . |
334 | p >-> map f = for p (\txt -> yield (T.map f txt)) | |
335 | #-} | |
336 | ||
31f41a5d | 337 | -- | Map a function over the characters of a text stream and concatenate the results |
91727d11 | 338 | concatMap |
339 | :: (Monad m) => (Char -> Text) -> Pipe Text Text m r | |
340 | concatMap f = P.map (T.concatMap f) | |
341 | {-# INLINABLE concatMap #-} | |
342 | ||
ff38b9f0 | 343 | {-# RULES "p >-> concatMap f" forall p f . |
344 | p >-> concatMap f = for p (\txt -> yield (T.concatMap f txt)) | |
345 | #-} | |
7faef8bc | 346 | |
347 | -- | Transform a Pipe of 'Text' into a Pipe of 'ByteString's using UTF-8 | |
a02a69ad | 348 | -- encoding; @encodeUtf8 = Pipes.Prelude.map TE.encodeUtf8@ so more complex |
349 | -- encoding pipes can easily be constructed with the functions in @Data.Text.Encoding@ | |
7faef8bc | 350 | encodeUtf8 :: Monad m => Pipe Text ByteString m r |
351 | encodeUtf8 = P.map TE.encodeUtf8 | |
352 | {-# INLINEABLE encodeUtf8 #-} | |
353 | ||
ff38b9f0 | 354 | {-# RULES "p >-> encodeUtf8" forall p . |
355 | p >-> encodeUtf8 = for p (\txt -> yield (TE.encodeUtf8 txt)) | |
356 | #-} | |
357 | ||
c0343bc9 | 358 | -- | Transform a Pipe of 'String's into one of 'Text' chunks |
7faef8bc | 359 | pack :: Monad m => Pipe String Text m r |
360 | pack = P.map T.pack | |
361 | {-# INLINEABLE pack #-} | |
362 | ||
ff38b9f0 | 363 | {-# RULES "p >-> pack" forall p . |
364 | p >-> pack = for p (\txt -> yield (T.pack txt)) | |
365 | #-} | |
366 | ||
367 | -- | Transform a Pipes of 'Text' chunks into one of 'String's | |
7faef8bc | 368 | unpack :: Monad m => Pipe Text String m r |
d4732515 | 369 | unpack = for cat (\t -> yield (T.unpack t)) |
7faef8bc | 370 | {-# INLINEABLE unpack #-} |
371 | ||
ff38b9f0 | 372 | {-# RULES "p >-> unpack" forall p . |
373 | p >-> unpack = for p (\txt -> yield (T.unpack txt)) | |
374 | #-} | |
d4732515 | 375 | |
c0343bc9 | 376 | -- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utility, |
7faef8bc | 377 | -- here acting on a 'Text' pipe, rather as they would on a lazy text |
378 | toCaseFold :: Monad m => Pipe Text Text m () | |
379 | toCaseFold = P.map T.toCaseFold | |
380 | {-# INLINEABLE toCaseFold #-} | |
381 | ||
ff38b9f0 | 382 | {-# RULES "p >-> toCaseFold" forall p . |
383 | p >-> toCaseFold = for p (\txt -> yield (T.toCaseFold txt)) | |
384 | #-} | |
385 | ||
386 | ||
c0343bc9 | 387 | -- | lowercase incoming 'Text' |
7faef8bc | 388 | toLower :: Monad m => Pipe Text Text m () |
389 | toLower = P.map T.toLower | |
390 | {-# INLINEABLE toLower #-} | |
391 | ||
ff38b9f0 | 392 | {-# RULES "p >-> toLower" forall p . |
393 | p >-> toLower = for p (\txt -> yield (T.toLower txt)) | |
394 | #-} | |
395 | ||
c0343bc9 | 396 | -- | uppercase incoming 'Text' |
7faef8bc | 397 | toUpper :: Monad m => Pipe Text Text m () |
398 | toUpper = P.map T.toUpper | |
399 | {-# INLINEABLE toUpper #-} | |
400 | ||
ff38b9f0 | 401 | {-# RULES "p >-> toUpper" forall p . |
402 | p >-> toUpper = for p (\txt -> yield (T.toUpper txt)) | |
403 | #-} | |
404 | ||
c0343bc9 | 405 | -- | Remove leading white space from an incoming succession of 'Text's |
7faef8bc | 406 | stripStart :: Monad m => Pipe Text Text m r |
407 | stripStart = do | |
408 | chunk <- await | |
409 | let text = T.stripStart chunk | |
410 | if T.null text | |
411 | then stripStart | |
412 | else cat | |
413 | {-# INLINEABLE stripStart #-} | |
414 | ||
31f41a5d | 415 | -- | @(take n)@ only allows @n@ individual characters to pass; |
416 | -- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass. | |
91727d11 | 417 | take :: (Monad m, Integral a) => a -> Pipe Text Text m () |
418 | take n0 = go n0 where | |
419 | go n | |
420 | | n <= 0 = return () | |
421 | | otherwise = do | |
31f41a5d | 422 | txt <- await |
423 | let len = fromIntegral (T.length txt) | |
91727d11 | 424 | if (len > n) |
31f41a5d | 425 | then yield (T.take (fromIntegral n) txt) |
91727d11 | 426 | else do |
31f41a5d | 427 | yield txt |
91727d11 | 428 | go (n - len) |
429 | {-# INLINABLE take #-} | |
430 | ||
31f41a5d | 431 | -- | @(drop n)@ drops the first @n@ characters |
91727d11 | 432 | drop :: (Monad m, Integral a) => a -> Pipe Text Text m r |
433 | drop n0 = go n0 where | |
434 | go n | |
435 | | n <= 0 = cat | |
436 | | otherwise = do | |
31f41a5d | 437 | txt <- await |
438 | let len = fromIntegral (T.length txt) | |
91727d11 | 439 | if (len >= n) |
440 | then do | |
31f41a5d | 441 | yield (T.drop (fromIntegral n) txt) |
91727d11 | 442 | cat |
443 | else go (n - len) | |
444 | {-# INLINABLE drop #-} | |
445 | ||
31f41a5d | 446 | -- | Take characters until they fail the predicate |
91727d11 | 447 | takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m () |
448 | takeWhile predicate = go | |
449 | where | |
450 | go = do | |
31f41a5d | 451 | txt <- await |
452 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 453 | if (T.null suffix) |
454 | then do | |
31f41a5d | 455 | yield txt |
91727d11 | 456 | go |
457 | else yield prefix | |
458 | {-# INLINABLE takeWhile #-} | |
459 | ||
31f41a5d | 460 | -- | Drop characters until they fail the predicate |
91727d11 | 461 | dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r |
462 | dropWhile predicate = go where | |
463 | go = do | |
31f41a5d | 464 | txt <- await |
465 | case T.findIndex (not . predicate) txt of | |
91727d11 | 466 | Nothing -> go |
467 | Just i -> do | |
31f41a5d | 468 | yield (T.drop i txt) |
91727d11 | 469 | cat |
470 | {-# INLINABLE dropWhile #-} | |
471 | ||
472 | -- | Only allows 'Char's to pass if they satisfy the predicate | |
473 | filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r | |
474 | filter predicate = P.map (T.filter predicate) | |
475 | {-# INLINABLE filter #-} | |
476 | ||
ff38b9f0 | 477 | {-# RULES "p >-> filter q" forall p q . |
478 | p >-> filter q = for p (\txt -> yield (T.filter q txt)) | |
479 | #-} | |
480 | ||
31f41a5d | 481 | -- | Strict left scan over the characters |
91727d11 | 482 | scan |
483 | :: (Monad m) | |
484 | => (Char -> Char -> Char) -> Char -> Pipe Text Text m r | |
485 | scan step begin = go begin | |
486 | where | |
31f41a5d | 487 | go c = do |
488 | txt <- await | |
489 | let txt' = T.scanl step c txt | |
490 | c' = T.last txt' | |
491 | yield txt' | |
492 | go c' | |
91727d11 | 493 | {-# INLINABLE scan #-} |
494 | ||
495 | {-| Fold a pure 'Producer' of strict 'Text's into a lazy | |
496 | 'TL.Text' | |
497 | -} | |
498 | toLazy :: Producer Text Identity () -> TL.Text | |
499 | toLazy = TL.fromChunks . P.toList | |
500 | {-# INLINABLE toLazy #-} | |
501 | ||
502 | {-| Fold an effectful 'Producer' of strict 'Text's into a lazy | |
503 | 'TL.Text' | |
504 | ||
505 | Note: 'toLazyM' is not an idiomatic use of @pipes@, but I provide it for | |
506 | simple testing purposes. Idiomatic @pipes@ style consumes the chunks | |
507 | immediately as they are generated instead of loading them all into memory. | |
508 | -} | |
509 | toLazyM :: (Monad m) => Producer Text m () -> m TL.Text | |
510 | toLazyM = liftM TL.fromChunks . P.toListM | |
511 | {-# INLINABLE toLazyM #-} | |
512 | ||
31f41a5d | 513 | -- | Reduce the text stream using a strict left fold over characters |
91727d11 | 514 | fold |
515 | :: Monad m | |
516 | => (x -> Char -> x) -> x -> (x -> r) -> Producer Text m () -> m r | |
31f41a5d | 517 | fold step begin done = P.fold (T.foldl' step) begin done |
91727d11 | 518 | {-# INLINABLE fold #-} |
519 | ||
520 | -- | Retrieve the first 'Char' | |
521 | head :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
522 | head = go | |
523 | where | |
524 | go p = do | |
525 | x <- nextChar p | |
526 | case x of | |
527 | Left _ -> return Nothing | |
31f41a5d | 528 | Right (c, _) -> return (Just c) |
91727d11 | 529 | {-# INLINABLE head #-} |
530 | ||
531 | -- | Retrieve the last 'Char' | |
532 | last :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
533 | last = go Nothing | |
534 | where | |
535 | go r p = do | |
536 | x <- next p | |
537 | case x of | |
538 | Left () -> return r | |
31f41a5d | 539 | Right (txt, p') -> |
540 | if (T.null txt) | |
91727d11 | 541 | then go r p' |
31f41a5d | 542 | else go (Just $ T.last txt) p' |
91727d11 | 543 | {-# INLINABLE last #-} |
544 | ||
545 | -- | Determine if the stream is empty | |
546 | null :: (Monad m) => Producer Text m () -> m Bool | |
547 | null = P.all T.null | |
548 | {-# INLINABLE null #-} | |
549 | ||
62e8521c | 550 | -- | Count the number of characters in the stream |
91727d11 | 551 | length :: (Monad m, Num n) => Producer Text m () -> m n |
31f41a5d | 552 | length = P.fold (\n txt -> n + fromIntegral (T.length txt)) 0 id |
91727d11 | 553 | {-# INLINABLE length #-} |
554 | ||
555 | -- | Fold that returns whether 'M.Any' received 'Char's satisfy the predicate | |
556 | any :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
557 | any predicate = P.any (T.any predicate) | |
558 | {-# INLINABLE any #-} | |
559 | ||
560 | -- | Fold that returns whether 'M.All' received 'Char's satisfy the predicate | |
561 | all :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
562 | all predicate = P.all (T.all predicate) | |
563 | {-# INLINABLE all #-} | |
564 | ||
62e8521c | 565 | -- | Return the maximum 'Char' within a text stream |
91727d11 | 566 | maximum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
567 | maximum = P.fold step Nothing id | |
568 | where | |
31f41a5d | 569 | step mc txt = |
570 | if (T.null txt) | |
571 | then mc | |
572 | else Just $ case mc of | |
573 | Nothing -> T.maximum txt | |
574 | Just c -> max c (T.maximum txt) | |
91727d11 | 575 | {-# INLINABLE maximum #-} |
576 | ||
62e8521c | 577 | -- | Return the minimum 'Char' within a text stream (surely very useful!) |
91727d11 | 578 | minimum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
579 | minimum = P.fold step Nothing id | |
580 | where | |
31f41a5d | 581 | step mc txt = |
582 | if (T.null txt) | |
583 | then mc | |
584 | else case mc of | |
585 | Nothing -> Just (T.minimum txt) | |
586 | Just c -> Just (min c (T.minimum txt)) | |
91727d11 | 587 | {-# INLINABLE minimum #-} |
588 | ||
91727d11 | 589 | -- | Find the first element in the stream that matches the predicate |
590 | find | |
591 | :: (Monad m) | |
592 | => (Char -> Bool) -> Producer Text m () -> m (Maybe Char) | |
593 | find predicate p = head (p >-> filter predicate) | |
594 | {-# INLINABLE find #-} | |
595 | ||
62e8521c | 596 | -- | Index into a text stream |
91727d11 | 597 | index |
598 | :: (Monad m, Integral a) | |
599 | => a-> Producer Text m () -> m (Maybe Char) | |
600 | index n p = head (p >-> drop n) | |
601 | {-# INLINABLE index #-} | |
602 | ||
63ea9ffd | 603 | |
31f41a5d | 604 | -- | Store a tally of how many segments match the given 'Text' |
605 | count :: (Monad m, Num n) => Text -> Producer Text m () -> m n | |
606 | count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c)) | |
607 | {-# INLINABLE count #-} | |
608 | ||
609 | #if MIN_VERSION_text(0,11,4) | |
610 | -- | Transform a Pipe of 'ByteString's expected to be UTF-8 encoded | |
611 | -- into a Pipe of Text | |
612 | decodeUtf8 | |
613 | :: Monad m | |
614 | => Producer ByteString m r -> Producer Text m (Producer ByteString m r) | |
615 | decodeUtf8 = go TE.streamDecodeUtf8 | |
616 | where go dec p = do | |
617 | x <- lift (next p) | |
618 | case x of | |
619 | Left r -> return (return r) | |
620 | Right (chunk, p') -> do | |
621 | let TE.Some text l dec' = dec chunk | |
622 | if B.null l | |
623 | then do | |
624 | yield text | |
625 | go dec' p' | |
626 | else return $ do | |
627 | yield l | |
628 | p' | |
629 | {-# INLINEABLE decodeUtf8 #-} | |
63ea9ffd | 630 | |
631 | -- | Transform a Pipe of 'ByteString's expected to be UTF-8 encoded | |
632 | -- into a Pipe of Text with a replacement function of type @String -> Maybe Word8 -> Maybe Char@ | |
633 | -- E.g. 'Data.Text.Encoding.Error.lenientDecode', which simply replaces bad bytes with \"�\" | |
634 | decodeUtf8With | |
635 | :: Monad m | |
636 | => TE.OnDecodeError | |
637 | -> Producer ByteString m r -> Producer Text m (Producer ByteString m r) | |
638 | decodeUtf8With onErr = go (TE.streamDecodeUtf8With onErr) | |
639 | where go dec p = do | |
640 | x <- lift (next p) | |
641 | case x of | |
642 | Left r -> return (return r) | |
643 | Right (chunk, p') -> do | |
644 | let TE.Some text l dec' = dec chunk | |
645 | if B.null l | |
646 | then do | |
647 | yield text | |
648 | go dec' p' | |
649 | else return $ do | |
650 | yield l | |
651 | p' | |
652 | {-# INLINEABLE decodeUtf8With #-} | |
a02a69ad | 653 | |
654 | -- | A simple pipe from 'ByteString' to 'Text'; a decoding error will arise | |
655 | -- with any chunk that contains a sequence of bytes that is unreadable. Otherwise | |
656 | -- only few bytes will only be moved from one chunk to the next before decoding. | |
657 | pipeDecodeUtf8 :: Monad m => Pipe ByteString Text m r | |
658 | pipeDecodeUtf8 = go TE.streamDecodeUtf8 | |
659 | where go dec = do chunk <- await | |
660 | case dec chunk of | |
661 | TE.Some text l dec' -> do yield text | |
662 | go dec' | |
663 | {-# INLINEABLE pipeDecodeUtf8 #-} | |
664 | ||
665 | -- | A simple pipe from 'ByteString' to 'Text' using a replacement function. | |
666 | pipeDecodeUtf8With | |
667 | :: Monad m | |
668 | => TE.OnDecodeError | |
669 | -> Pipe ByteString Text m r | |
670 | pipeDecodeUtf8With onErr = go (TE.streamDecodeUtf8With onErr) | |
671 | where go dec = do chunk <- await | |
672 | case dec chunk of | |
673 | TE.Some text l dec' -> do yield text | |
674 | go dec' | |
675 | {-# INLINEABLE pipeDecodeUtf8With #-} | |
31f41a5d | 676 | #endif |
677 | ||
678 | -- | Splits a 'Producer' after the given number of characters | |
91727d11 | 679 | splitAt |
680 | :: (Monad m, Integral n) | |
681 | => n | |
682 | -> Producer Text m r | |
683 | -> Producer' Text m (Producer Text m r) | |
684 | splitAt = go | |
685 | where | |
686 | go 0 p = return p | |
687 | go n p = do | |
688 | x <- lift (next p) | |
689 | case x of | |
690 | Left r -> return (return r) | |
31f41a5d | 691 | Right (txt, p') -> do |
692 | let len = fromIntegral (T.length txt) | |
91727d11 | 693 | if (len <= n) |
694 | then do | |
31f41a5d | 695 | yield txt |
91727d11 | 696 | go (n - len) p' |
697 | else do | |
31f41a5d | 698 | let (prefix, suffix) = T.splitAt (fromIntegral n) txt |
91727d11 | 699 | yield prefix |
700 | return (yield suffix >> p') | |
701 | {-# INLINABLE splitAt #-} | |
702 | ||
31f41a5d | 703 | -- | Split a text stream into 'FreeT'-delimited text streams of fixed size |
91727d11 | 704 | chunksOf |
705 | :: (Monad m, Integral n) | |
706 | => n -> Producer Text m r -> FreeT (Producer Text m) m r | |
707 | chunksOf n p0 = PP.FreeT (go p0) | |
708 | where | |
709 | go p = do | |
710 | x <- next p | |
711 | return $ case x of | |
712 | Left r -> PP.Pure r | |
31f41a5d | 713 | Right (txt, p') -> PP.Free $ do |
714 | p'' <- splitAt n (yield txt >> p') | |
91727d11 | 715 | return $ PP.FreeT (go p'') |
716 | {-# INLINABLE chunksOf #-} | |
717 | ||
31f41a5d | 718 | {-| Split a text stream in two, where the first text stream is the longest |
719 | consecutive group of text that satisfy the predicate | |
91727d11 | 720 | -} |
721 | span | |
722 | :: (Monad m) | |
723 | => (Char -> Bool) | |
724 | -> Producer Text m r | |
725 | -> Producer' Text m (Producer Text m r) | |
726 | span predicate = go | |
727 | where | |
728 | go p = do | |
729 | x <- lift (next p) | |
730 | case x of | |
731 | Left r -> return (return r) | |
31f41a5d | 732 | Right (txt, p') -> do |
733 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 734 | if (T.null suffix) |
735 | then do | |
31f41a5d | 736 | yield txt |
91727d11 | 737 | go p' |
738 | else do | |
739 | yield prefix | |
740 | return (yield suffix >> p') | |
741 | {-# INLINABLE span #-} | |
742 | ||
62e8521c | 743 | {-| Split a text stream in two, where the first text stream is the longest |
744 | consecutive group of characters that don't satisfy the predicate | |
91727d11 | 745 | -} |
746 | break | |
747 | :: (Monad m) | |
748 | => (Char -> Bool) | |
749 | -> Producer Text m r | |
750 | -> Producer Text m (Producer Text m r) | |
751 | break predicate = span (not . predicate) | |
752 | {-# INLINABLE break #-} | |
753 | ||
62e8521c | 754 | {-| Split a text stream into sub-streams delimited by characters that satisfy the |
91727d11 | 755 | predicate |
756 | -} | |
757 | splitWith | |
758 | :: (Monad m) | |
759 | => (Char -> Bool) | |
760 | -> Producer Text m r | |
761 | -> PP.FreeT (Producer Text m) m r | |
762 | splitWith predicate p0 = PP.FreeT (go0 p0) | |
763 | where | |
764 | go0 p = do | |
765 | x <- next p | |
766 | case x of | |
767 | Left r -> return (PP.Pure r) | |
31f41a5d | 768 | Right (txt, p') -> |
769 | if (T.null txt) | |
91727d11 | 770 | then go0 p' |
771 | else return $ PP.Free $ do | |
31f41a5d | 772 | p'' <- span (not . predicate) (yield txt >> p') |
91727d11 | 773 | return $ PP.FreeT (go1 p'') |
774 | go1 p = do | |
775 | x <- nextChar p | |
776 | return $ case x of | |
777 | Left r -> PP.Pure r | |
778 | Right (_, p') -> PP.Free $ do | |
779 | p'' <- span (not . predicate) p' | |
780 | return $ PP.FreeT (go1 p'') | |
781 | {-# INLINABLE splitWith #-} | |
782 | ||
31f41a5d | 783 | -- | Split a text stream using the given 'Char' as the delimiter |
91727d11 | 784 | split :: (Monad m) |
785 | => Char | |
786 | -> Producer Text m r | |
787 | -> FreeT (Producer Text m) m r | |
31f41a5d | 788 | split c = splitWith (c ==) |
91727d11 | 789 | {-# INLINABLE split #-} |
790 | ||
62e8521c | 791 | {-| Group a text stream into 'FreeT'-delimited text streams using the supplied |
91727d11 | 792 | equality predicate |
793 | -} | |
794 | groupBy | |
795 | :: (Monad m) | |
796 | => (Char -> Char -> Bool) | |
797 | -> Producer Text m r | |
798 | -> FreeT (Producer Text m) m r | |
799 | groupBy equal p0 = PP.FreeT (go p0) | |
800 | where | |
801 | go p = do | |
802 | x <- next p | |
803 | case x of | |
804 | Left r -> return (PP.Pure r) | |
31f41a5d | 805 | Right (txt, p') -> case (T.uncons txt) of |
91727d11 | 806 | Nothing -> go p' |
31f41a5d | 807 | Just (c, _) -> do |
91727d11 | 808 | return $ PP.Free $ do |
31f41a5d | 809 | p'' <- span (equal c) (yield txt >> p') |
91727d11 | 810 | return $ PP.FreeT (go p'') |
811 | {-# INLINABLE groupBy #-} | |
812 | ||
62e8521c | 813 | -- | Group a text stream into 'FreeT'-delimited text streams of identical characters |
91727d11 | 814 | group |
815 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
816 | group = groupBy (==) | |
817 | {-# INLINABLE group #-} | |
818 | ||
62e8521c | 819 | {-| Split a text stream into 'FreeT'-delimited lines |
91727d11 | 820 | -} |
821 | lines | |
822 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
823 | lines p0 = PP.FreeT (go0 p0) | |
824 | where | |
825 | go0 p = do | |
826 | x <- next p | |
827 | case x of | |
828 | Left r -> return (PP.Pure r) | |
31f41a5d | 829 | Right (txt, p') -> |
830 | if (T.null txt) | |
91727d11 | 831 | then go0 p' |
31f41a5d | 832 | else return $ PP.Free $ go1 (yield txt >> p') |
91727d11 | 833 | go1 p = do |
834 | p' <- break ('\n' ==) p | |
b4d21c02 | 835 | return $ PP.FreeT $ do |
836 | x <- nextChar p' | |
837 | case x of | |
838 | Left r -> return $ PP.Pure r | |
839 | Right (_, p'') -> go0 p'' | |
91727d11 | 840 | {-# INLINABLE lines #-} |
91727d11 | 841 | |
31f41a5d | 842 | |
843 | ||
844 | -- | Split a text stream into 'FreeT'-delimited words | |
91727d11 | 845 | words |
846 | :: (Monad m) => Producer Text m r -> FreeT (Producer Text m) m r | |
cf10d6f1 | 847 | words = go |
91727d11 | 848 | where |
cf10d6f1 | 849 | go p = PP.FreeT $ do |
850 | x <- next (p >-> dropWhile isSpace) | |
851 | return $ case x of | |
852 | Left r -> PP.Pure r | |
853 | Right (bs, p') -> PP.Free $ do | |
854 | p'' <- break isSpace (yield bs >> p') | |
855 | return (go p'') | |
91727d11 | 856 | {-# INLINABLE words #-} |
857 | ||
cf10d6f1 | 858 | |
62e8521c | 859 | -- | Intersperse a 'Char' in between the characters of the text stream |
91727d11 | 860 | intersperse |
861 | :: (Monad m) => Char -> Producer Text m r -> Producer Text m r | |
31f41a5d | 862 | intersperse c = go0 |
91727d11 | 863 | where |
864 | go0 p = do | |
865 | x <- lift (next p) | |
866 | case x of | |
867 | Left r -> return r | |
31f41a5d | 868 | Right (txt, p') -> do |
869 | yield (T.intersperse c txt) | |
91727d11 | 870 | go1 p' |
871 | go1 p = do | |
872 | x <- lift (next p) | |
873 | case x of | |
874 | Left r -> return r | |
31f41a5d | 875 | Right (txt, p') -> do |
876 | yield (T.singleton c) | |
877 | yield (T.intersperse c txt) | |
91727d11 | 878 | go1 p' |
879 | {-# INLINABLE intersperse #-} | |
880 | ||
31f41a5d | 881 | {-| 'intercalate' concatenates the 'FreeT'-delimited text streams after |
882 | interspersing a text stream in between them | |
91727d11 | 883 | -} |
884 | intercalate | |
885 | :: (Monad m) | |
886 | => Producer Text m () | |
887 | -> FreeT (Producer Text m) m r | |
888 | -> Producer Text m r | |
889 | intercalate p0 = go0 | |
890 | where | |
891 | go0 f = do | |
892 | x <- lift (PP.runFreeT f) | |
893 | case x of | |
894 | PP.Pure r -> return r | |
895 | PP.Free p -> do | |
896 | f' <- p | |
897 | go1 f' | |
898 | go1 f = do | |
899 | x <- lift (PP.runFreeT f) | |
900 | case x of | |
901 | PP.Pure r -> return r | |
902 | PP.Free p -> do | |
903 | p0 | |
904 | f' <- p | |
905 | go1 f' | |
906 | {-# INLINABLE intercalate #-} | |
907 | ||
62e8521c | 908 | {-| Join 'FreeT'-delimited lines into a text stream |
91727d11 | 909 | -} |
910 | unlines | |
911 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
912 | unlines = go | |
913 | where | |
914 | go f = do | |
915 | x <- lift (PP.runFreeT f) | |
916 | case x of | |
917 | PP.Pure r -> return r | |
918 | PP.Free p -> do | |
919 | f' <- p | |
920 | yield $ T.singleton '\n' | |
921 | go f' | |
922 | {-# INLINABLE unlines #-} | |
923 | ||
31f41a5d | 924 | {-| Join 'FreeT'-delimited words into a text stream |
91727d11 | 925 | -} |
926 | unwords | |
927 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
928 | unwords = intercalate (yield $ T.pack " ") | |
929 | {-# INLINABLE unwords #-} | |
930 | ||
931 | {- $parse | |
31f41a5d | 932 | The following parsing utilities are single-character analogs of the ones found |
933 | @pipes-parse@. | |
91727d11 | 934 | -} |
935 | ||
91727d11 | 936 | {- $reexports |
31f41a5d | 937 | @Pipes.Text.Parse@ re-exports 'nextChar', 'drawChar', 'unDrawChar', 'peekChar', and 'isEndOfChars'. |
91727d11 | 938 | |
939 | @Data.Text@ re-exports the 'Text' type. | |
940 | ||
91727d11 | 941 | @Pipes.Parse@ re-exports 'input', 'concat', and 'FreeT' (the type). |
942 | -} |