Streamly.Internal.Unicode.Stream

Setup

To execute the code examples provided in this module in ghci, please run the following commands first.

>>> :m

>>> import qualified Streamly.Data.Fold as Fold
>>> import qualified Streamly.Data.Stream as Stream
>>> import qualified Streamly.Unicode.Stream as Unicode

For APIs that have not been released yet.

>>> :set -XMagicHash
>>> import qualified Streamly.Internal.Unicode.Stream as Unicode

Construction (Decoding)

decodeLatin1 :: Monad m => Stream m Word8 -> Stream m Char

Decode a stream of bytes to Unicode characters by mapping each byte to a corresponding Unicode Char in 0-255 range.

UTF-8 Decoding

data CodingFailureMode

Constructors

TransliterateCodingFailure

ErrorOnCodingFailure

DropOnCodingFailure

Instances

Show CodingFailureMode

Defined in Streamly.Internal.Unicode.Stream

Methods

showsPrec :: Int -> CodingFailureMode -> ShowS

show :: CodingFailureMode -> String

showList :: [CodingFailureMode] -> ShowS

writeCharUtf8' :: Monad m => Parser Word8 m Char

parseCharUtf8With :: Monad m => CodingFailureMode -> Parser Word8 m Char

decodeUtf8 :: Monad m => Stream m Word8 -> Stream m Char

Decode a UTF-8 encoded bytestream to a stream of Unicode characters. Any invalid codepoint encountered is replaced with the unicode replacement character.

decodeUtf8' :: Monad m => Stream m Word8 -> Stream m Char

Decode a UTF-8 encoded bytestream to a stream of Unicode characters. The function throws an error if an invalid codepoint is encountered.

decodeUtf8_ :: Monad m => Stream m Word8 -> Stream m Char

Decode a UTF-8 encoded bytestream to a stream of Unicode characters. Any invalid codepoint encountered is dropped.

Resumable UTF-8 Decoding

data DecodeError

Constructors

DecodeError !DecodeState !CodePoint

Instances

Show DecodeError

Defined in Streamly.Internal.Unicode.Stream

Methods

showsPrec :: Int -> DecodeError -> ShowS

show :: DecodeError -> String

showList :: [DecodeError] -> ShowS

type DecodeState = Word8

type CodePoint = Int

decodeUtf8Either :: Monad m => Stream m Word8 -> Stream m (Either DecodeError Char)

Pre-release

resumeDecodeUtf8Either :: Monad m => DecodeState -> CodePoint -> Stream m Word8 -> Stream m (Either DecodeError Char)

Pre-release

UTF-8 Array Stream Decoding

decodeUtf8Chunks :: MonadIO m => Stream m (Array Word8) -> Stream m Char

Like decodeUtf8 but for a chunked stream. It may be slightly faster than flattening the stream and then decoding with decodeUtf8.

decodeUtf8Chunks' :: MonadIO m => Stream m (Array Word8) -> Stream m Char

Like 'decodeUtf8'' but for a chunked stream. It may be slightly faster than flattening the stream and then decoding with 'decodeUtf8''.

decodeUtf8Chunks_ :: MonadIO m => Stream m (Array Word8) -> Stream m Char

Like decodeUtf8_ but for a chunked stream. It may be slightly faster than flattening the stream and then decoding with decodeUtf8_.

Elimination (Encoding)

Latin1 Encoding

encodeLatin1 :: Monad m => Stream m Char -> Stream m Word8

Like encodeLatin1' but silently maps input codepoints beyond 255 to arbitrary Latin1 chars in 0-255 range. No error or exception is thrown when such mapping occurs.

encodeLatin1' :: Monad m => Stream m Char -> Stream m Word8

Encode a stream of Unicode characters to bytes by mapping each character to a byte in 0-255 range. Throws an error if the input stream contains characters beyond 255.

encodeLatin1_ :: Monad m => Stream m Char -> Stream m Word8

Like encodeLatin1 but drops the input characters beyond 255.

UTF-8 Encoding

readCharUtf8' :: Monad m => Unfold m Char Word8

readCharUtf8 :: Monad m => Unfold m Char Word8

readCharUtf8_ :: Monad m => Unfold m Char Word8

encodeUtf8 :: Monad m => Stream m Char -> Stream m Word8

Encode a stream of Unicode characters to a UTF-8 encoded bytestream. Any Invalid characters (U+D800-U+D8FF) in the input stream are replaced by the Unicode replacement character U+FFFD.

encodeUtf8' :: Monad m => Stream m Char -> Stream m Word8

Encode a stream of Unicode characters to a UTF-8 encoded bytestream. When any invalid character (U+D800-U+D8FF) is encountered in the input stream the function errors out.

encodeUtf8_ :: Monad m => Stream m Char -> Stream m Word8

Encode a stream of Unicode characters to a UTF-8 encoded bytestream. Any Invalid characters (U+D800-U+D8FF) in the input stream are dropped.

encodeStrings :: MonadIO m => (Stream m Char -> Stream m Word8) -> Stream m String -> Stream m (Array Word8)

Encode a stream of String using the supplied encoding scheme. Each string is encoded as an Array Word8.

Transformation

stripHead :: Monad m => Stream m Char -> Stream m Char

Remove leading whitespace from a string.

stripHead = Stream.dropWhile isSpace

Pre-release

lines :: Monad m => Fold m Char b -> Stream m Char -> Stream m b

Fold each line of the stream using the supplied Fold and stream the result.

>>> Stream.fold Fold.toList $ Unicode.lines Fold.toList (Stream.fromList "lines\nthis\nstring\n\n\n")
["lines","this","string","",""]

lines = Stream.splitOnSuffix (== '\n')

Pre-release

words :: Monad m => Fold m Char b -> Stream m Char -> Stream m b

Fold each word of the stream using the supplied Fold and stream the result.

>>> Stream.fold Fold.toList $ Unicode.words Fold.toList (Stream.fromList "fold these     words")
["fold","these","words"]

words = Stream.wordsBy isSpace

Pre-release

unlines :: MonadIO m => Unfold m a Char -> Stream m a -> Stream m Char

Unfold a stream to character streams using the supplied Unfold and concat the results suffixing a newline character \n to each stream.

unlines = Stream.interposeSuffix 'n'
unlines = Stream.intercalateSuffix Unfold.fromList "n"

Pre-release

unwords :: MonadIO m => Unfold m a Char -> Stream m a -> Stream m Char

Unfold the elements of a stream to character streams using the supplied Unfold and concat the results with a whitespace character infixed between the streams.

unwords = Stream.interpose ' '
unwords = Stream.intercalate Unfold.fromList " "

Pre-release

StreamD UTF8 Encoding / Decoding transformations.

decodeUtf8D :: Monad m => Stream m Word8 -> Stream m Char

decodeUtf8D' :: Monad m => Stream m Word8 -> Stream m Char

decodeUtf8D_ :: Monad m => Stream m Word8 -> Stream m Char

encodeUtf8D :: Monad m => Stream m Char -> Stream m Word8

See section "3.9 Unicode Encoding Forms" in https://www.unicode.org/versions/Unicode13.0.0/UnicodeStandard-13.0.pdf

encodeUtf8D' :: Monad m => Stream m Char -> Stream m Word8

encodeUtf8D_ :: Monad m => Stream m Char -> Stream m Word8

decodeUtf8EitherD :: Monad m => Stream m Word8 -> Stream m (Either DecodeError Char)

resumeDecodeUtf8EitherD :: Monad m => DecodeState -> CodePoint -> Stream m Word8 -> Stream m (Either DecodeError Char)

Decoding String Literals

fromStr# :: MonadIO m => Addr# -> Stream m Char

Read UTF-8 encoded bytes as chars from an Addr# until a 0 byte is encountered, the 0 byte is not included in the stream.

Unsafe: The caller is responsible for safe addressing.

Note that this is completely safe when reading from Haskell string literals because they are guaranteed to be NULL terminated:

>>> Stream.fold Fold.toList (Unicode.fromStr# "Haskell"#)
"Haskell"

Deprecations

decodeUtf8Lax :: Monad m => Stream m Word8 -> Stream m Char

Deprecated: Please use decodeUtf8 instead

Same as decodeUtf8

encodeLatin1Lax :: Monad m => Stream m Char -> Stream m Word8

Deprecated: Please use encodeLatin1 instead

Same as encodeLatin1

encodeUtf8Lax :: Monad m => Stream m Char -> Stream m Word8

Deprecated: Please use encodeUtf8 instead

Same as encodeUtf8