diff options
Diffstat (limited to 'Pipes')
-rw-r--r-- | Pipes/Text.hs | 16 | ||||
-rw-r--r-- | Pipes/Text/Encoding.hs | 2 |
2 files changed, 10 insertions, 8 deletions
diff --git a/Pipes/Text.hs b/Pipes/Text.hs index d5b93f1..2f69806 100644 --- a/Pipes/Text.hs +++ b/Pipes/Text.hs | |||
@@ -1,7 +1,7 @@ | |||
1 | {-# LANGUAGE RankNTypes, TypeFamilies, BangPatterns, Trustworthy #-} | 1 | {-# LANGUAGE RankNTypes, TypeFamilies, BangPatterns, Trustworthy #-} |
2 | 2 | ||
3 | {-| This package provides @pipes@ utilities for \'text streams\', which are | 3 | {-| This package provides @pipes@ utilities for \'text streams\', which are |
4 | streams of 'Text' chunks. The individual chunks are uniformly @strict@, and you | 4 | streams of 'Text' chunks. The individual chunks are uniformly @strict@, and thus you |
5 | will generally want @Data.Text@ in scope. But the type @Producer Text m r@ is | 5 | will generally want @Data.Text@ in scope. But the type @Producer Text m r@ is |
6 | in some ways the pipes equivalent of the lazy @Text@ type. | 6 | in some ways the pipes equivalent of the lazy @Text@ type. |
7 | 7 | ||
@@ -9,8 +9,8 @@ | |||
9 | the 'pure' functions in | 9 | the 'pure' functions in |
10 | <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>. | 10 | <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>. |
11 | They transform, divide, group and fold text streams. Though @Producer Text m r@ | 11 | They transform, divide, group and fold text streams. Though @Producer Text m r@ |
12 | is \'effectful\' Text, functions | 12 | is the type of \'effectful Text\', the functions in this module are \'pure\' |
13 | in this module are \'pure\' in the sense that they are uniformly monad-independent. | 13 | in the sense that they are uniformly monad-independent. |
14 | Simple IO operations are defined in @Pipes.Text.IO@ -- as lazy IO @Text@ | 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@ | 15 | operations are in @Data.Text.Lazy.IO@. Interoperation with @ByteString@ |
16 | is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@. | 16 | is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@. |
@@ -49,7 +49,10 @@ | |||
49 | <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html pipes-parse> | 49 | <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html pipes-parse> |
50 | sense.) | 50 | sense.) |
51 | Each such expression, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the | 51 | Each such expression, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the |
52 | intuitively corresponding function when used with @view@ or @(^.)@. | 52 | intuitively corresponding function when used with @view@ or @(^.)@. The lens combinators |
53 | you will find indispensible are \'view\'/ '(^.)', 'zoom' and probably 'over', which | ||
54 | are supplied by both <http://hackage.haskell.org/package/lens lens> and | ||
55 | <http://hackage.haskell.org/package/lens-family lens-family> | ||
53 | 56 | ||
54 | A more important difference the example reveals is in the types closely associated with | 57 | 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@ | 58 | the central type, @Producer Text m r@. In @Data.Text@ and @Data.Text.Lazy@ |
@@ -62,15 +65,14 @@ | |||
62 | which relate a Text with a pair or list of Texts. The corresponding functions here (taking | 65 | which relate a Text with a pair or list of Texts. The corresponding functions here (taking |
63 | account of \'lensification\') are | 66 | account of \'lensification\') are |
64 | 67 | ||
65 | > view . splitAt :: (Monad m, Integral n) | 68 | > view . splitAt :: (Monad m, Integral n) => n -> Producer Text m r -> Producer Text.Text m (Producer Text.Text m r) |
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 | 69 | > view lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r |
68 | > view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r | 70 | > view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r |
69 | 71 | ||
70 | In the type @Producer Text m (Producer Text m r)@ the second | 72 | In the type @Producer Text m (Producer Text m r)@ the second |
71 | element of the \'pair\' of of \'effectful Texts\' cannot simply be retrieved | 73 | 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 | 74 | 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@, | 75 | of the first element to arrive at the second Text stream. Similarly in @FreeT (Producer Text m) m r@, |
74 | which corresponds with @[Text]@, on cannot simply drop 10 Producers and take the others; | 76 | 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. | 77 | we can only get to the ones we want to take by working through their predecessors. |
76 | 78 | ||
diff --git a/Pipes/Text/Encoding.hs b/Pipes/Text/Encoding.hs index a1a0113..e6fc6bf 100644 --- a/Pipes/Text/Encoding.hs +++ b/Pipes/Text/Encoding.hs | |||
@@ -189,7 +189,7 @@ mkCodec dec enc = \k p0 -> fmap (\p -> join (for p (yield . enc))) (k (dec p0)) | |||
189 | > decode utf8 Byte.stdin :: Producer Text IO (Producer ByteString IO r) | 189 | > decode utf8 Byte.stdin :: Producer Text IO (Producer ByteString IO r) |
190 | > Bytes.stdin ^. utf8 :: Producer Text IO (Producer ByteString IO r) | 190 | > Bytes.stdin ^. utf8 :: Producer Text IO (Producer ByteString IO r) |
191 | 191 | ||
192 | Uses of a codec with @view@ / @(^.)@ / 'decode' can always be replaced by the specialized | 192 | Uses of a codec with @view@ or @(^.)@ or 'decode' can always be replaced by the specialized |
193 | decoding functions exported here, e.g. | 193 | decoding functions exported here, e.g. |
194 | 194 | ||
195 | > decodeUtf8 :: Producer ByteString m r -> Producer Text m (Producer ByteString m r) | 195 | > decodeUtf8 :: Producer ByteString m r -> Producer Text m (Producer ByteString m r) |