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1 | {-# LANGUAGE RankNTypes, TypeFamilies, BangPatterns, Trustworthy #-} |
2 | ||
74377aa0 | 3 | {-| This package provides @pipes@ utilities for \'text streams\', which are |
0ac0c414 | 4 | streams of 'Text' chunks. The individual chunks are uniformly @strict@, and you |
5 | will generally want @Data.Text@ in scope. But the type @Producer Text m r@ is | |
74377aa0 | 6 | in some ways the pipes equivalent of the lazy @Text@ type. |
0ac0c414 | 7 | |
8 | This module provides many functions equivalent in one way or another to | |
9 | the 'pure' functions in | |
10 | <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>. | |
74377aa0 | 11 | They transform, divide, group and fold text streams. Though @Producer Text m r@ |
12 | is \'effectful\' Text, functions | |
0ac0c414 | 13 | in this module are \'pure\' in the sense that they are uniformly monad-independent. |
74377aa0 | 14 | Simple IO operations are defined in @Pipes.Text.IO@ -- as lazy IO @Text@ |
15 | operations are in @Data.Text.Lazy.IO@. Interoperation with @ByteString@ | |
16 | is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@. | |
17 | ||
18 | The Text type exported by @Data.Text.Lazy@ is basically '[Text]'. The implementation | |
19 | is arranged so that the individual strict 'Text' chunks are kept to a reasonable size; | |
20 | the user is not aware of the divisions between the connected 'Text' chunks. | |
21 | So also here: the functions in this module are designed to operate on streams that | |
0ac0c414 | 22 | are insensitive to text boundaries. This means that they may freely split |
74377aa0 | 23 | text into smaller texts and /discard empty texts/. However, the objective is |
24 | that they should /never concatenate texts/ in order to provide strict upper | |
25 | bounds on memory usage. | |
26 | ||
0ac0c414 | 27 | For example, to stream only the first three lines of 'stdin' to 'stdout' you |
31f41a5d | 28 | might write: |
91727d11 | 29 | |
30 | > import Pipes | |
31f41a5d | 31 | > import qualified Pipes.Text as Text |
74377aa0 | 32 | > import qualified Pipes.Text.IO as Text |
33 | > import Pipes.Group | |
34 | > import Lens.Family | |
35 | > | |
31f41a5d | 36 | > main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout |
74377aa0 | 37 | > where |
38 | > takeLines n = Text.unlines . takes' n . view Text.lines | |
39 | > -- or equivalently: | |
40 | > -- takeLines n = over Text.lines (takes' n) | |
91727d11 | 41 | |
31f41a5d | 42 | The above program will never bring more than one chunk of text (~ 32 KB) into |
74377aa0 | 43 | memory, no matter how long the lines are. |
44 | ||
45 | As this example shows, one superficial difference from @Data.Text.Lazy@ | |
46 | is that many of the operations, like 'lines', | |
47 | are \'lensified\'; this has a number of advantages where it is possible, in particular | |
e7ad3643 | 48 | it facilitates their use with 'Parser's of Text (in the general |
49 | <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html pipes-parse> | |
50 | sense.) | |
51 | Each such expression, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the | |
52 | intuitively corresponding function when used with @view@ or @(^.)@. | |
74377aa0 | 53 | |
54 | A more important difference the example reveals is in the types closely associated with | |
55 | the central type, @Producer Text m r@. In @Data.Text@ and @Data.Text.Lazy@ | |
56 | we find functions like | |
57 | ||
58 | > splitAt :: Int -> Text -> (Text, Text) | |
59 | > lines :: Int -> Text -> [Text] | |
e7ad3643 | 60 | > chunksOf :: Int -> Text -> [Text] |
74377aa0 | 61 | |
62 | which relate a Text with a pair or list of Texts. The corresponding functions here (taking | |
63 | account of \'lensification\') are | |
64 | ||
65 | > view . splitAt :: (Monad m, Integral n) | |
66 | > => n -> Producer Text m r -> Producer Text.Text m (Producer Text.Text m r) | |
67 | > view lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r | |
e7ad3643 | 68 | > view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r |
74377aa0 | 69 | |
e7ad3643 | 70 | In the type @Producer Text m (Producer Text m r)@ the second |
74377aa0 | 71 | element of the \'pair\' of of \'effectful Texts\' cannot simply be retrieved |
72 | with 'snd'. This is an \'effectful\' pair, and one must work through the effects | |
73 | of the first element to arrive at the second. Similarly in @FreeT (Producer Text m) m r@, | |
74 | which corresponds with @[Text]@, on cannot simply drop 10 Producers and take the others; | |
75 | we can only get to the ones we want to take by working through their predecessors. | |
76 | ||
77 | Some of the types may be more readable if you imagine that we have introduced | |
78 | our own type synonyms | |
79 | ||
80 | > type Text m r = Producer T.Text m r | |
81 | > type Texts m r = FreeT (Producer T.Text m) m r | |
82 | ||
83 | Then we would think of the types above as | |
84 | ||
85 | > view . splitAt :: (Monad m, Integral n) => n -> Text m r -> Text m (Text m r) | |
86 | > view lines :: (Monad m) => Text m r -> Texts m r | |
e7ad3643 | 87 | > view . chunksOf :: (Monad m, Integral n) => n -> Text m r -> Texts m r |
74377aa0 | 88 | |
89 | which brings one closer to the types of the similar functions in @Data.Text.Lazy@ | |
90 | ||
91727d11 | 91 | -} |
92 | ||
7faef8bc | 93 | module Pipes.Text ( |
91727d11 | 94 | -- * Producers |
1a83ae4e | 95 | fromLazy |
91727d11 | 96 | |
97 | -- * Pipes | |
1677dc12 | 98 | , map |
99 | , concatMap | |
100 | , take | |
101 | , drop | |
102 | , takeWhile | |
103 | , dropWhile | |
104 | , filter | |
105 | , scan | |
1677dc12 | 106 | , pack |
107 | , unpack | |
108 | , toCaseFold | |
109 | , toLower | |
110 | , toUpper | |
111 | , stripStart | |
91727d11 | 112 | |
113 | -- * Folds | |
1677dc12 | 114 | , toLazy |
115 | , toLazyM | |
116 | , foldChars | |
117 | , head | |
118 | , last | |
119 | , null | |
120 | , length | |
121 | , any | |
122 | , all | |
123 | , maximum | |
124 | , minimum | |
125 | , find | |
126 | , index | |
127 | , count | |
128 | ||
129 | -- * Primitive Character Parsers | |
1677dc12 | 130 | , nextChar |
131 | , drawChar | |
132 | , unDrawChar | |
133 | , peekChar | |
9e9bb0ce | 134 | , isEndOfChars |
1677dc12 | 135 | |
136 | -- * Parsing Lenses | |
9e9bb0ce | 137 | , splitAt |
1677dc12 | 138 | , span |
139 | , break | |
140 | , groupBy | |
141 | , group | |
9e9bb0ce | 142 | , word |
143 | , line | |
1677dc12 | 144 | |
145 | -- * FreeT Splitters | |
146 | , chunksOf | |
147 | , splitsWith | |
0f8c6f1b | 148 | , splits |
1a83ae4e | 149 | , groupsBy |
150 | , groups | |
1677dc12 | 151 | , lines |
152 | , words | |
153 | ||
91727d11 | 154 | -- * Transformations |
1677dc12 | 155 | , intersperse |
9e9bb0ce | 156 | , packChars |
31f41a5d | 157 | |
91727d11 | 158 | -- * Joiners |
1677dc12 | 159 | , intercalate |
160 | , unlines | |
161 | , unwords | |
9e9bb0ce | 162 | |
1a83ae4e | 163 | -- * Re-exports |
91727d11 | 164 | -- $reexports |
1677dc12 | 165 | , module Data.ByteString |
166 | , module Data.Text | |
167 | , module Data.Profunctor | |
1677dc12 | 168 | , module Pipes.Parse |
7ed76745 | 169 | , module Pipes.Group |
91727d11 | 170 | ) where |
171 | ||
0f8c6f1b | 172 | import Control.Applicative ((<*)) |
70125641 | 173 | import Control.Monad (liftM, join) |
9e9bb0ce | 174 | import Control.Monad.Trans.State.Strict (StateT(..), modify) |
91727d11 | 175 | import qualified Data.Text as T |
91727d11 | 176 | import Data.Text (Text) |
177 | import qualified Data.Text.Lazy as TL | |
91727d11 | 178 | import Data.Text.Lazy.Internal (foldrChunks, defaultChunkSize) |
31f41a5d | 179 | import Data.ByteString (ByteString) |
1677dc12 | 180 | import Data.Functor.Constant (Constant(Constant, getConstant)) |
91727d11 | 181 | import Data.Functor.Identity (Identity) |
1677dc12 | 182 | import Data.Profunctor (Profunctor) |
183 | import qualified Data.Profunctor | |
91727d11 | 184 | import Pipes |
7fc48f7c | 185 | import Pipes.Group (concats, intercalates, FreeT(..), FreeF(..)) |
7ed76745 | 186 | import qualified Pipes.Group as PG |
91727d11 | 187 | import qualified Pipes.Parse as PP |
7ed76745 | 188 | import Pipes.Parse (Parser) |
91727d11 | 189 | import qualified Pipes.Prelude as P |
91727d11 | 190 | import Data.Char (isSpace) |
1a83ae4e | 191 | import Data.Word (Word8) |
1677dc12 | 192 | |
91727d11 | 193 | import Prelude hiding ( |
194 | all, | |
195 | any, | |
196 | break, | |
197 | concat, | |
198 | concatMap, | |
199 | drop, | |
200 | dropWhile, | |
201 | elem, | |
202 | filter, | |
203 | head, | |
204 | last, | |
205 | lines, | |
206 | length, | |
207 | map, | |
208 | maximum, | |
209 | minimum, | |
210 | notElem, | |
211 | null, | |
212 | readFile, | |
213 | span, | |
214 | splitAt, | |
215 | take, | |
216 | takeWhile, | |
217 | unlines, | |
218 | unwords, | |
219 | words, | |
220 | writeFile ) | |
221 | ||
222 | -- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's | |
223 | fromLazy :: (Monad m) => TL.Text -> Producer' Text m () | |
224 | fromLazy = foldrChunks (\e a -> yield e >> a) (return ()) | |
ca6f90a0 | 225 | {-# INLINE fromLazy #-} |
91727d11 | 226 | |
1677dc12 | 227 | |
228 | type Lens' a b = forall f . Functor f => (b -> f b) -> (a -> f a) | |
229 | ||
230 | type Iso' a b = forall f p . (Functor f, Profunctor p) => p b (f b) -> p a (f a) | |
231 | ||
232 | (^.) :: a -> ((b -> Constant b b) -> (a -> Constant b a)) -> b | |
233 | a ^. lens = getConstant (lens Constant a) | |
234 | ||
235 | ||
91727d11 | 236 | -- | Apply a transformation to each 'Char' in the stream |
237 | map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r | |
238 | map f = P.map (T.map f) | |
239 | {-# INLINABLE map #-} | |
240 | ||
ff38b9f0 | 241 | {-# RULES "p >-> map f" forall p f . |
242 | p >-> map f = for p (\txt -> yield (T.map f txt)) | |
243 | #-} | |
244 | ||
31f41a5d | 245 | -- | Map a function over the characters of a text stream and concatenate the results |
91727d11 | 246 | concatMap |
247 | :: (Monad m) => (Char -> Text) -> Pipe Text Text m r | |
248 | concatMap f = P.map (T.concatMap f) | |
249 | {-# INLINABLE concatMap #-} | |
250 | ||
ff38b9f0 | 251 | {-# RULES "p >-> concatMap f" forall p f . |
252 | p >-> concatMap f = for p (\txt -> yield (T.concatMap f txt)) | |
253 | #-} | |
7faef8bc | 254 | |
ff38b9f0 | 255 | |
c0343bc9 | 256 | -- | Transform a Pipe of 'String's into one of 'Text' chunks |
7faef8bc | 257 | pack :: Monad m => Pipe String Text m r |
258 | pack = P.map T.pack | |
259 | {-# INLINEABLE pack #-} | |
260 | ||
ff38b9f0 | 261 | {-# RULES "p >-> pack" forall p . |
262 | p >-> pack = for p (\txt -> yield (T.pack txt)) | |
263 | #-} | |
264 | ||
265 | -- | Transform a Pipes of 'Text' chunks into one of 'String's | |
7faef8bc | 266 | unpack :: Monad m => Pipe Text String m r |
d4732515 | 267 | unpack = for cat (\t -> yield (T.unpack t)) |
7faef8bc | 268 | {-# INLINEABLE unpack #-} |
269 | ||
ff38b9f0 | 270 | {-# RULES "p >-> unpack" forall p . |
271 | p >-> unpack = for p (\txt -> yield (T.unpack txt)) | |
272 | #-} | |
d4732515 | 273 | |
b0d86a59 | 274 | -- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utilities, |
275 | -- here acting as 'Text' pipes, rather as they would on a lazy text | |
7faef8bc | 276 | toCaseFold :: Monad m => Pipe Text Text m () |
277 | toCaseFold = P.map T.toCaseFold | |
278 | {-# INLINEABLE toCaseFold #-} | |
279 | ||
ff38b9f0 | 280 | {-# RULES "p >-> toCaseFold" forall p . |
281 | p >-> toCaseFold = for p (\txt -> yield (T.toCaseFold txt)) | |
282 | #-} | |
283 | ||
284 | ||
c0343bc9 | 285 | -- | lowercase incoming 'Text' |
7faef8bc | 286 | toLower :: Monad m => Pipe Text Text m () |
287 | toLower = P.map T.toLower | |
288 | {-# INLINEABLE toLower #-} | |
289 | ||
ff38b9f0 | 290 | {-# RULES "p >-> toLower" forall p . |
291 | p >-> toLower = for p (\txt -> yield (T.toLower txt)) | |
292 | #-} | |
293 | ||
c0343bc9 | 294 | -- | uppercase incoming 'Text' |
7faef8bc | 295 | toUpper :: Monad m => Pipe Text Text m () |
296 | toUpper = P.map T.toUpper | |
297 | {-# INLINEABLE toUpper #-} | |
298 | ||
ff38b9f0 | 299 | {-# RULES "p >-> toUpper" forall p . |
300 | p >-> toUpper = for p (\txt -> yield (T.toUpper txt)) | |
301 | #-} | |
302 | ||
c0343bc9 | 303 | -- | Remove leading white space from an incoming succession of 'Text's |
7faef8bc | 304 | stripStart :: Monad m => Pipe Text Text m r |
305 | stripStart = do | |
306 | chunk <- await | |
307 | let text = T.stripStart chunk | |
308 | if T.null text | |
309 | then stripStart | |
b0d86a59 | 310 | else do yield text |
311 | cat | |
7faef8bc | 312 | {-# INLINEABLE stripStart #-} |
313 | ||
31f41a5d | 314 | -- | @(take n)@ only allows @n@ individual characters to pass; |
315 | -- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass. | |
91727d11 | 316 | take :: (Monad m, Integral a) => a -> Pipe Text Text m () |
317 | take n0 = go n0 where | |
318 | go n | |
319 | | n <= 0 = return () | |
320 | | otherwise = do | |
31f41a5d | 321 | txt <- await |
322 | let len = fromIntegral (T.length txt) | |
91727d11 | 323 | if (len > n) |
31f41a5d | 324 | then yield (T.take (fromIntegral n) txt) |
91727d11 | 325 | else do |
31f41a5d | 326 | yield txt |
91727d11 | 327 | go (n - len) |
328 | {-# INLINABLE take #-} | |
329 | ||
31f41a5d | 330 | -- | @(drop n)@ drops the first @n@ characters |
91727d11 | 331 | drop :: (Monad m, Integral a) => a -> Pipe Text Text m r |
332 | drop n0 = go n0 where | |
333 | go n | |
334 | | n <= 0 = cat | |
335 | | otherwise = do | |
31f41a5d | 336 | txt <- await |
337 | let len = fromIntegral (T.length txt) | |
91727d11 | 338 | if (len >= n) |
339 | then do | |
31f41a5d | 340 | yield (T.drop (fromIntegral n) txt) |
91727d11 | 341 | cat |
342 | else go (n - len) | |
343 | {-# INLINABLE drop #-} | |
344 | ||
31f41a5d | 345 | -- | Take characters until they fail the predicate |
91727d11 | 346 | takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m () |
347 | takeWhile predicate = go | |
348 | where | |
349 | go = do | |
31f41a5d | 350 | txt <- await |
351 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 352 | if (T.null suffix) |
353 | then do | |
31f41a5d | 354 | yield txt |
91727d11 | 355 | go |
356 | else yield prefix | |
357 | {-# INLINABLE takeWhile #-} | |
358 | ||
31f41a5d | 359 | -- | Drop characters until they fail the predicate |
91727d11 | 360 | dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r |
361 | dropWhile predicate = go where | |
362 | go = do | |
31f41a5d | 363 | txt <- await |
364 | case T.findIndex (not . predicate) txt of | |
91727d11 | 365 | Nothing -> go |
366 | Just i -> do | |
31f41a5d | 367 | yield (T.drop i txt) |
91727d11 | 368 | cat |
369 | {-# INLINABLE dropWhile #-} | |
370 | ||
371 | -- | Only allows 'Char's to pass if they satisfy the predicate | |
372 | filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r | |
373 | filter predicate = P.map (T.filter predicate) | |
374 | {-# INLINABLE filter #-} | |
375 | ||
ff38b9f0 | 376 | {-# RULES "p >-> filter q" forall p q . |
377 | p >-> filter q = for p (\txt -> yield (T.filter q txt)) | |
378 | #-} | |
379 | ||
31f41a5d | 380 | -- | Strict left scan over the characters |
91727d11 | 381 | scan |
382 | :: (Monad m) | |
383 | => (Char -> Char -> Char) -> Char -> Pipe Text Text m r | |
11645cdc GG |
384 | scan step begin = do |
385 | yield (T.singleton begin) | |
386 | go begin | |
91727d11 | 387 | where |
31f41a5d | 388 | go c = do |
389 | txt <- await | |
390 | let txt' = T.scanl step c txt | |
391 | c' = T.last txt' | |
11645cdc | 392 | yield (T.tail txt') |
31f41a5d | 393 | go c' |
91727d11 | 394 | {-# INLINABLE scan #-} |
395 | ||
396 | {-| Fold a pure 'Producer' of strict 'Text's into a lazy | |
397 | 'TL.Text' | |
398 | -} | |
399 | toLazy :: Producer Text Identity () -> TL.Text | |
400 | toLazy = TL.fromChunks . P.toList | |
401 | {-# INLINABLE toLazy #-} | |
402 | ||
403 | {-| Fold an effectful 'Producer' of strict 'Text's into a lazy | |
404 | 'TL.Text' | |
405 | ||
406 | Note: 'toLazyM' is not an idiomatic use of @pipes@, but I provide it for | |
407 | simple testing purposes. Idiomatic @pipes@ style consumes the chunks | |
408 | immediately as they are generated instead of loading them all into memory. | |
409 | -} | |
410 | toLazyM :: (Monad m) => Producer Text m () -> m TL.Text | |
411 | toLazyM = liftM TL.fromChunks . P.toListM | |
412 | {-# INLINABLE toLazyM #-} | |
413 | ||
31f41a5d | 414 | -- | Reduce the text stream using a strict left fold over characters |
64e03122 | 415 | foldChars |
91727d11 | 416 | :: Monad m |
417 | => (x -> Char -> x) -> x -> (x -> r) -> Producer Text m () -> m r | |
64e03122 | 418 | foldChars step begin done = P.fold (T.foldl' step) begin done |
1677dc12 | 419 | {-# INLINABLE foldChars #-} |
91727d11 | 420 | |
421 | -- | Retrieve the first 'Char' | |
422 | head :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
423 | head = go | |
424 | where | |
425 | go p = do | |
426 | x <- nextChar p | |
427 | case x of | |
428 | Left _ -> return Nothing | |
31f41a5d | 429 | Right (c, _) -> return (Just c) |
91727d11 | 430 | {-# INLINABLE head #-} |
431 | ||
432 | -- | Retrieve the last 'Char' | |
433 | last :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
434 | last = go Nothing | |
435 | where | |
436 | go r p = do | |
437 | x <- next p | |
438 | case x of | |
439 | Left () -> return r | |
31f41a5d | 440 | Right (txt, p') -> |
441 | if (T.null txt) | |
91727d11 | 442 | then go r p' |
31f41a5d | 443 | else go (Just $ T.last txt) p' |
91727d11 | 444 | {-# INLINABLE last #-} |
445 | ||
446 | -- | Determine if the stream is empty | |
447 | null :: (Monad m) => Producer Text m () -> m Bool | |
448 | null = P.all T.null | |
449 | {-# INLINABLE null #-} | |
450 | ||
62e8521c | 451 | -- | Count the number of characters in the stream |
91727d11 | 452 | length :: (Monad m, Num n) => Producer Text m () -> m n |
31f41a5d | 453 | length = P.fold (\n txt -> n + fromIntegral (T.length txt)) 0 id |
91727d11 | 454 | {-# INLINABLE length #-} |
455 | ||
456 | -- | Fold that returns whether 'M.Any' received 'Char's satisfy the predicate | |
457 | any :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
458 | any predicate = P.any (T.any predicate) | |
459 | {-# INLINABLE any #-} | |
460 | ||
461 | -- | Fold that returns whether 'M.All' received 'Char's satisfy the predicate | |
462 | all :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
463 | all predicate = P.all (T.all predicate) | |
464 | {-# INLINABLE all #-} | |
465 | ||
62e8521c | 466 | -- | Return the maximum 'Char' within a text stream |
91727d11 | 467 | maximum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
468 | maximum = P.fold step Nothing id | |
469 | where | |
31f41a5d | 470 | step mc txt = |
471 | if (T.null txt) | |
472 | then mc | |
473 | else Just $ case mc of | |
474 | Nothing -> T.maximum txt | |
475 | Just c -> max c (T.maximum txt) | |
91727d11 | 476 | {-# INLINABLE maximum #-} |
477 | ||
62e8521c | 478 | -- | Return the minimum 'Char' within a text stream (surely very useful!) |
91727d11 | 479 | minimum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
480 | minimum = P.fold step Nothing id | |
481 | where | |
31f41a5d | 482 | step mc txt = |
483 | if (T.null txt) | |
484 | then mc | |
485 | else case mc of | |
486 | Nothing -> Just (T.minimum txt) | |
487 | Just c -> Just (min c (T.minimum txt)) | |
91727d11 | 488 | {-# INLINABLE minimum #-} |
489 | ||
91727d11 | 490 | -- | Find the first element in the stream that matches the predicate |
491 | find | |
492 | :: (Monad m) | |
493 | => (Char -> Bool) -> Producer Text m () -> m (Maybe Char) | |
494 | find predicate p = head (p >-> filter predicate) | |
495 | {-# INLINABLE find #-} | |
496 | ||
62e8521c | 497 | -- | Index into a text stream |
91727d11 | 498 | index |
499 | :: (Monad m, Integral a) | |
500 | => a-> Producer Text m () -> m (Maybe Char) | |
501 | index n p = head (p >-> drop n) | |
502 | {-# INLINABLE index #-} | |
503 | ||
63ea9ffd | 504 | |
31f41a5d | 505 | -- | Store a tally of how many segments match the given 'Text' |
506 | count :: (Monad m, Num n) => Text -> Producer Text m () -> m n | |
507 | count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c)) | |
508 | {-# INLINABLE count #-} | |
509 | ||
9e9bb0ce | 510 | |
1a83ae4e | 511 | -- | Consume the first character from a stream of 'Text' |
512 | -- | |
513 | -- 'next' either fails with a 'Left' if the 'Producer' has no more characters or | |
514 | -- succeeds with a 'Right' providing the next character and the remainder of the | |
515 | -- 'Producer'. | |
9e9bb0ce | 516 | |
9e9bb0ce | 517 | nextChar |
518 | :: (Monad m) | |
519 | => Producer Text m r | |
520 | -> m (Either r (Char, Producer Text m r)) | |
521 | nextChar = go | |
522 | where | |
523 | go p = do | |
524 | x <- next p | |
525 | case x of | |
526 | Left r -> return (Left r) | |
527 | Right (txt, p') -> case (T.uncons txt) of | |
528 | Nothing -> go p' | |
529 | Just (c, txt') -> return (Right (c, yield txt' >> p')) | |
530 | {-# INLINABLE nextChar #-} | |
531 | ||
1a83ae4e | 532 | -- | Draw one 'Char' from a stream of 'Text', returning 'Left' if the 'Producer' is empty |
533 | ||
9e9bb0ce | 534 | drawChar :: (Monad m) => Parser Text m (Maybe Char) |
535 | drawChar = do | |
536 | x <- PP.draw | |
537 | case x of | |
538 | Nothing -> return Nothing | |
539 | Just txt -> case (T.uncons txt) of | |
540 | Nothing -> drawChar | |
541 | Just (c, txt') -> do | |
542 | PP.unDraw txt' | |
543 | return (Just c) | |
544 | {-# INLINABLE drawChar #-} | |
545 | ||
546 | -- | Push back a 'Char' onto the underlying 'Producer' | |
547 | unDrawChar :: (Monad m) => Char -> Parser Text m () | |
548 | unDrawChar c = modify (yield (T.singleton c) >>) | |
549 | {-# INLINABLE unDrawChar #-} | |
550 | ||
551 | {-| 'peekChar' checks the first 'Char' in the stream, but uses 'unDrawChar' to | |
552 | push the 'Char' back | |
553 | ||
554 | > peekChar = do | |
555 | > x <- drawChar | |
556 | > case x of | |
557 | > Left _ -> return () | |
558 | > Right c -> unDrawChar c | |
559 | > return x | |
1a83ae4e | 560 | |
9e9bb0ce | 561 | -} |
1a83ae4e | 562 | |
9e9bb0ce | 563 | peekChar :: (Monad m) => Parser Text m (Maybe Char) |
564 | peekChar = do | |
565 | x <- drawChar | |
566 | case x of | |
567 | Nothing -> return () | |
568 | Just c -> unDrawChar c | |
569 | return x | |
570 | {-# INLINABLE peekChar #-} | |
571 | ||
572 | {-| Check if the underlying 'Producer' has no more characters | |
573 | ||
574 | Note that this will skip over empty 'Text' chunks, unlike | |
575 | 'PP.isEndOfInput' from @pipes-parse@, which would consider | |
576 | an empty 'Text' a valid bit of input. | |
577 | ||
578 | > isEndOfChars = liftM isLeft peekChar | |
579 | -} | |
580 | isEndOfChars :: (Monad m) => Parser Text m Bool | |
581 | isEndOfChars = do | |
582 | x <- peekChar | |
583 | return (case x of | |
584 | Nothing -> True | |
585 | Just _-> False ) | |
586 | {-# INLINABLE isEndOfChars #-} | |
587 | ||
588 | ||
31f41a5d | 589 | -- | Splits a 'Producer' after the given number of characters |
91727d11 | 590 | splitAt |
591 | :: (Monad m, Integral n) | |
592 | => n | |
9e9bb0ce | 593 | -> Lens' (Producer Text m r) |
594 | (Producer Text m (Producer Text m r)) | |
595 | splitAt n0 k p0 = fmap join (k (go n0 p0)) | |
91727d11 | 596 | where |
597 | go 0 p = return p | |
598 | go n p = do | |
599 | x <- lift (next p) | |
600 | case x of | |
601 | Left r -> return (return r) | |
31f41a5d | 602 | Right (txt, p') -> do |
603 | let len = fromIntegral (T.length txt) | |
91727d11 | 604 | if (len <= n) |
605 | then do | |
31f41a5d | 606 | yield txt |
91727d11 | 607 | go (n - len) p' |
608 | else do | |
31f41a5d | 609 | let (prefix, suffix) = T.splitAt (fromIntegral n) txt |
91727d11 | 610 | yield prefix |
611 | return (yield suffix >> p') | |
612 | {-# INLINABLE splitAt #-} | |
613 | ||
91727d11 | 614 | |
1a83ae4e | 615 | -- | Split a text stream in two, producing the longest |
616 | -- consecutive group of characters that satisfies the predicate | |
617 | -- and returning the rest | |
618 | ||
91727d11 | 619 | span |
620 | :: (Monad m) | |
621 | => (Char -> Bool) | |
9e9bb0ce | 622 | -> Lens' (Producer Text m r) |
623 | (Producer Text m (Producer Text m r)) | |
624 | span predicate k p0 = fmap join (k (go p0)) | |
91727d11 | 625 | where |
626 | go p = do | |
627 | x <- lift (next p) | |
628 | case x of | |
629 | Left r -> return (return r) | |
31f41a5d | 630 | Right (txt, p') -> do |
631 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 632 | if (T.null suffix) |
633 | then do | |
31f41a5d | 634 | yield txt |
91727d11 | 635 | go p' |
636 | else do | |
637 | yield prefix | |
638 | return (yield suffix >> p') | |
639 | {-# INLINABLE span #-} | |
640 | ||
1a83ae4e | 641 | {-| Split a text stream in two, producing the longest |
62e8521c | 642 | consecutive group of characters that don't satisfy the predicate |
91727d11 | 643 | -} |
644 | break | |
645 | :: (Monad m) | |
646 | => (Char -> Bool) | |
9e9bb0ce | 647 | -> Lens' (Producer Text m r) |
648 | (Producer Text m (Producer Text m r)) | |
91727d11 | 649 | break predicate = span (not . predicate) |
650 | {-# INLINABLE break #-} | |
651 | ||
9e9bb0ce | 652 | {-| Improper lens that splits after the first group of equivalent Chars, as |
653 | defined by the given equivalence relation | |
654 | -} | |
655 | groupBy | |
656 | :: (Monad m) | |
657 | => (Char -> Char -> Bool) | |
658 | -> Lens' (Producer Text m r) | |
659 | (Producer Text m (Producer Text m r)) | |
660 | groupBy equals k p0 = fmap join (k ((go p0))) where | |
661 | go p = do | |
662 | x <- lift (next p) | |
663 | case x of | |
664 | Left r -> return (return r) | |
665 | Right (txt, p') -> case T.uncons txt of | |
666 | Nothing -> go p' | |
667 | Just (c, _) -> (yield txt >> p') ^. span (equals c) | |
668 | {-# INLINABLE groupBy #-} | |
669 | ||
670 | -- | Improper lens that splits after the first succession of identical 'Char' s | |
671 | group :: Monad m | |
672 | => Lens' (Producer Text m r) | |
673 | (Producer Text m (Producer Text m r)) | |
674 | group = groupBy (==) | |
675 | {-# INLINABLE group #-} | |
676 | ||
677 | {-| Improper lens that splits a 'Producer' after the first word | |
678 | ||
679 | Unlike 'words', this does not drop leading whitespace | |
680 | -} | |
681 | word :: (Monad m) | |
682 | => Lens' (Producer Text m r) | |
683 | (Producer Text m (Producer Text m r)) | |
684 | word k p0 = fmap join (k (to p0)) | |
685 | where | |
686 | to p = do | |
687 | p' <- p^.span isSpace | |
688 | p'^.break isSpace | |
689 | {-# INLINABLE word #-} | |
690 | ||
691 | ||
692 | line :: (Monad m) | |
693 | => Lens' (Producer Text m r) | |
694 | (Producer Text m (Producer Text m r)) | |
695 | line = break (== '\n') | |
696 | ||
697 | {-# INLINABLE line #-} | |
698 | ||
699 | ||
700 | -- | Intersperse a 'Char' in between the characters of stream of 'Text' | |
701 | intersperse | |
702 | :: (Monad m) => Char -> Producer Text m r -> Producer Text m r | |
703 | intersperse c = go0 | |
704 | where | |
705 | go0 p = do | |
706 | x <- lift (next p) | |
707 | case x of | |
708 | Left r -> return r | |
709 | Right (txt, p') -> do | |
710 | yield (T.intersperse c txt) | |
711 | go1 p' | |
712 | go1 p = do | |
713 | x <- lift (next p) | |
714 | case x of | |
715 | Left r -> return r | |
716 | Right (txt, p') -> do | |
717 | yield (T.singleton c) | |
718 | yield (T.intersperse c txt) | |
719 | go1 p' | |
720 | {-# INLINABLE intersperse #-} | |
721 | ||
722 | ||
723 | ||
724 | -- | Improper isomorphism between a 'Producer' of 'ByteString's and 'Word8's | |
725 | packChars :: Monad m => Iso' (Producer Char m x) (Producer Text m x) | |
726 | packChars = Data.Profunctor.dimap to (fmap from) | |
727 | where | |
728 | -- to :: Monad m => Producer Char m x -> Producer Text m x | |
7ed76745 | 729 | to p = PG.folds step id done (p^.PG.chunksOf defaultChunkSize) |
9e9bb0ce | 730 | |
731 | step diffAs c = diffAs . (c:) | |
732 | ||
733 | done diffAs = T.pack (diffAs []) | |
734 | ||
735 | -- from :: Monad m => Producer Text m x -> Producer Char m x | |
736 | from p = for p (each . T.unpack) | |
737 | {-# INLINABLE packChars #-} | |
738 | ||
0f8c6f1b | 739 | |
740 | -- | Split a text stream into 'FreeT'-delimited text streams of fixed size | |
741 | chunksOf | |
742 | :: (Monad m, Integral n) | |
743 | => n -> Lens' (Producer Text m r) | |
744 | (FreeT (Producer Text m) m r) | |
745 | chunksOf n k p0 = fmap concats (k (FreeT (go p0))) | |
746 | where | |
747 | go p = do | |
748 | x <- next p | |
749 | return $ case x of | |
7ed76745 | 750 | Left r -> Pure r |
751 | Right (txt, p') -> Free $ do | |
0f8c6f1b | 752 | p'' <- (yield txt >> p') ^. splitAt n |
7ed76745 | 753 | return $ FreeT (go p'') |
0f8c6f1b | 754 | {-# INLINABLE chunksOf #-} |
755 | ||
756 | ||
62e8521c | 757 | {-| Split a text stream into sub-streams delimited by characters that satisfy the |
91727d11 | 758 | predicate |
759 | -} | |
1677dc12 | 760 | splitsWith |
91727d11 | 761 | :: (Monad m) |
762 | => (Char -> Bool) | |
763 | -> Producer Text m r | |
7ed76745 | 764 | -> FreeT (Producer Text m) m r |
765 | splitsWith predicate p0 = FreeT (go0 p0) | |
91727d11 | 766 | where |
767 | go0 p = do | |
768 | x <- next p | |
769 | case x of | |
7ed76745 | 770 | Left r -> return (Pure r) |
31f41a5d | 771 | Right (txt, p') -> |
772 | if (T.null txt) | |
91727d11 | 773 | then go0 p' |
7ed76745 | 774 | else return $ Free $ do |
9e9bb0ce | 775 | p'' <- (yield txt >> p') ^. span (not . predicate) |
7ed76745 | 776 | return $ FreeT (go1 p'') |
91727d11 | 777 | go1 p = do |
778 | x <- nextChar p | |
779 | return $ case x of | |
7ed76745 | 780 | Left r -> Pure r |
781 | Right (_, p') -> Free $ do | |
9e9bb0ce | 782 | p'' <- p' ^. span (not . predicate) |
7ed76745 | 783 | return $ FreeT (go1 p'') |
1677dc12 | 784 | {-# INLINABLE splitsWith #-} |
91727d11 | 785 | |
31f41a5d | 786 | -- | Split a text stream using the given 'Char' as the delimiter |
0f8c6f1b | 787 | splits :: (Monad m) |
91727d11 | 788 | => Char |
0f8c6f1b | 789 | -> Lens' (Producer Text m r) |
790 | (FreeT (Producer Text m) m r) | |
791 | splits c k p = | |
7ed76745 | 792 | fmap (PG.intercalates (yield (T.singleton c))) (k (splitsWith (c ==) p)) |
0f8c6f1b | 793 | {-# INLINABLE splits #-} |
794 | ||
795 | {-| Isomorphism between a stream of 'Text' and groups of equivalent 'Char's , using the | |
796 | given equivalence relation | |
797 | -} | |
798 | groupsBy | |
799 | :: Monad m | |
800 | => (Char -> Char -> Bool) | |
801 | -> Lens' (Producer Text m x) (FreeT (Producer Text m) m x) | |
7ed76745 | 802 | groupsBy equals k p0 = fmap concats (k (FreeT (go p0))) where |
0f8c6f1b | 803 | go p = do x <- next p |
7ed76745 | 804 | case x of Left r -> return (Pure r) |
0f8c6f1b | 805 | Right (bs, p') -> case T.uncons bs of |
806 | Nothing -> go p' | |
7ed76745 | 807 | Just (c, _) -> do return $ Free $ do |
0f8c6f1b | 808 | p'' <- (yield bs >> p')^.span (equals c) |
7ed76745 | 809 | return $ FreeT (go p'') |
0f8c6f1b | 810 | {-# INLINABLE groupsBy #-} |
811 | ||
812 | ||
813 | -- | Like 'groupsBy', where the equality predicate is ('==') | |
814 | groups | |
815 | :: Monad m | |
816 | => Lens' (Producer Text m x) (FreeT (Producer Text m) m x) | |
817 | groups = groupsBy (==) | |
818 | {-# INLINABLE groups #-} | |
819 | ||
91727d11 | 820 | |
91727d11 | 821 | |
62e8521c | 822 | {-| Split a text stream into 'FreeT'-delimited lines |
91727d11 | 823 | -} |
824 | lines | |
0f8c6f1b | 825 | :: (Monad m) => Iso' (Producer Text m r) (FreeT (Producer Text m) m r) |
826 | lines = Data.Profunctor.dimap _lines (fmap _unlines) | |
91727d11 | 827 | where |
7ed76745 | 828 | _lines p0 = FreeT (go0 p0) |
0f8c6f1b | 829 | where |
830 | go0 p = do | |
831 | x <- next p | |
832 | case x of | |
7ed76745 | 833 | Left r -> return (Pure r) |
0f8c6f1b | 834 | Right (txt, p') -> |
835 | if (T.null txt) | |
836 | then go0 p' | |
7ed76745 | 837 | else return $ Free $ go1 (yield txt >> p') |
0f8c6f1b | 838 | go1 p = do |
839 | p' <- p ^. break ('\n' ==) | |
7ed76745 | 840 | return $ FreeT $ do |
0f8c6f1b | 841 | x <- nextChar p' |
842 | case x of | |
7ed76745 | 843 | Left r -> return $ Pure r |
0f8c6f1b | 844 | Right (_, p'') -> go0 p'' |
845 | -- _unlines | |
846 | -- :: Monad m | |
847 | -- => FreeT (Producer Text m) m x -> Producer Text m x | |
7fc48f7c | 848 | _unlines = concats . PG.maps (<* yield (T.singleton '\n')) |
849 | ||
0f8c6f1b | 850 | |
91727d11 | 851 | {-# INLINABLE lines #-} |
91727d11 | 852 | |
31f41a5d | 853 | |
31f41a5d | 854 | -- | Split a text stream into 'FreeT'-delimited words |
91727d11 | 855 | words |
0f8c6f1b | 856 | :: (Monad m) => Iso' (Producer Text m r) (FreeT (Producer Text m) m r) |
857 | words = Data.Profunctor.dimap go (fmap _unwords) | |
91727d11 | 858 | where |
7ed76745 | 859 | go p = FreeT $ do |
cf10d6f1 | 860 | x <- next (p >-> dropWhile isSpace) |
861 | return $ case x of | |
7ed76745 | 862 | Left r -> Pure r |
863 | Right (bs, p') -> Free $ do | |
9e9bb0ce | 864 | p'' <- (yield bs >> p') ^. break isSpace |
cf10d6f1 | 865 | return (go p'') |
7ed76745 | 866 | _unwords = PG.intercalates (yield $ T.singleton ' ') |
0f8c6f1b | 867 | |
91727d11 | 868 | {-# INLINABLE words #-} |
869 | ||
cf10d6f1 | 870 | |
31f41a5d | 871 | {-| 'intercalate' concatenates the 'FreeT'-delimited text streams after |
872 | interspersing a text stream in between them | |
91727d11 | 873 | -} |
874 | intercalate | |
875 | :: (Monad m) | |
876 | => Producer Text m () | |
877 | -> FreeT (Producer Text m) m r | |
878 | -> Producer Text m r | |
879 | intercalate p0 = go0 | |
880 | where | |
881 | go0 f = do | |
7ed76745 | 882 | x <- lift (runFreeT f) |
91727d11 | 883 | case x of |
7ed76745 | 884 | Pure r -> return r |
885 | Free p -> do | |
91727d11 | 886 | f' <- p |
887 | go1 f' | |
888 | go1 f = do | |
7ed76745 | 889 | x <- lift (runFreeT f) |
91727d11 | 890 | case x of |
7ed76745 | 891 | Pure r -> return r |
892 | Free p -> do | |
91727d11 | 893 | p0 |
894 | f' <- p | |
895 | go1 f' | |
896 | {-# INLINABLE intercalate #-} | |
897 | ||
62e8521c | 898 | {-| Join 'FreeT'-delimited lines into a text stream |
91727d11 | 899 | -} |
900 | unlines | |
901 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
902 | unlines = go | |
903 | where | |
904 | go f = do | |
7ed76745 | 905 | x <- lift (runFreeT f) |
91727d11 | 906 | case x of |
7ed76745 | 907 | Pure r -> return r |
908 | Free p -> do | |
91727d11 | 909 | f' <- p |
910 | yield $ T.singleton '\n' | |
911 | go f' | |
912 | {-# INLINABLE unlines #-} | |
913 | ||
31f41a5d | 914 | {-| Join 'FreeT'-delimited words into a text stream |
91727d11 | 915 | -} |
916 | unwords | |
917 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
7fc48f7c | 918 | unwords = intercalate (yield $ T.singleton ' ') |
91727d11 | 919 | {-# INLINABLE unwords #-} |
920 | ||
91727d11 | 921 | |
91727d11 | 922 | {- $reexports |
91727d11 | 923 | |
924 | @Data.Text@ re-exports the 'Text' type. | |
925 | ||
0f8c6f1b | 926 | @Pipes.Parse@ re-exports 'input', 'concat', 'FreeT' (the type) and the 'Parse' synonym. |
64e03122 | 927 | -} |
928 | ||
bbdfd305 | 929 |