Copyright	(c) 2008 2009 Tom Harper (c) 2009 2010 Bryan O'Sullivan (c) 2009 Duncan Coutts
License	BSD-style
Maintainer	bos@serpentine.com
Stability	experimental
Portability	GHC
Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.Text.Internal

Contents

Types
Construction
Safety
Code that must be here for accessibility
Utilities
Checked multiplication
Debugging
Conversions

Description

A module containing private Text internals. This exposes the Text representation and low level construction functions. Modules which extend the Text system may need to use this module.

You should not use this module unless you are determined to monkey with the internals, as the functions here do just about nothing to preserve data invariants. You have been warned!

Synopsis

data Text = Text !Array !Int !Int
type StrictText = Text
text :: Array -> Int -> Int -> Text
textP :: Array -> Int -> Int -> Text
safe :: Char -> Char
empty :: Text
append :: Text -> Text -> Text
firstf :: (a -> c) -> Maybe (a, b) -> Maybe (c, b)
mul :: Int -> Int -> Int
mul32 :: Int32 -> Int32 -> Int32
mul64 :: Int64 -> Int64 -> Int64
showText :: Text -> String
pack :: String -> Text

Types

Internally, the Text type is represented as an array of Word8 UTF-8 code units. The offset and length fields in the constructor are in these units, not units of Char.

Invariants that all functions must maintain:

Since the Text type uses UTF-8 internally, it cannot represent characters in the reserved surrogate code point range U+D800 to U+DFFF. To maintain this invariant, the safe function maps Char values in this range to the replacement character (U+FFFD, '�').
Offset and length must point to a valid UTF-8 sequence of bytes. Violation of this may cause memory access violation and divergence.

data Text Source #

A space efficient, packed, unboxed Unicode text type.

Constructors

Text
Fields !Array bytearray encoded as UTF-8 !Int offset in bytes (not in Char!), pointing to a start of UTF-8 sequence !Int length in bytes (not in Char!), pointing to an end of UTF-8 sequence

Instances

Instances details

Data Text Source #	This instance preserves data abstraction at the cost of inefficiency. We omit reflection services for the sake of data abstraction. This instance was created by copying the updated behavior of `Data.Set.Set` and `Data.Map.Map`. If you feel a mistake has been made, please feel free to submit improvements. The original discussion is archived here: could we get a Data instance for Data.Text.Text? The followup discussion that changed the behavior of `Set` and `Map` is archived here: Proposal: Allow gunfold for Data.Map, ...
Instance details Defined in Data.Text Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Text -> c Text # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Text # toConstr :: Text -> Constr # dataTypeOf :: Text -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Text) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Text) # gmapT :: (forall b. Data b => b -> b) -> Text -> Text # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Text -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Text -> r # gmapQ :: (forall d. Data d => d -> u) -> Text -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Text -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Text -> m Text # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Text -> m Text # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Text -> m Text #
IsString Text Source #	Performs replacement on invalid scalar values: `>>>` `:set -XOverloadedStrings``>>>` `"\55555" :: Text`"\65533"
Instance details Defined in Data.Text Methods fromString :: String -> Text #
Monoid Text Source #
Instance details Defined in Data.Text Methods mempty :: Text # mappend :: Text -> Text -> Text # mconcat :: [Text] -> Text #
Semigroup Text Source #	Since: 1.2.2.0
Instance details Defined in Data.Text Methods (<>) :: Text -> Text -> Text # sconcat :: NonEmpty Text -> Text # stimes :: Integral b => b -> Text -> Text #
IsList Text Source #	Performs replacement on invalid scalar values: `>>>` `:set -XOverloadedLists``>>>` `['\55555'] :: Text`"\65533" Since: 1.2.0.0
Instance details Defined in Data.Text Associated Types type Item Text # Methods fromList :: [Item Text] -> Text # fromListN :: Int -> [Item Text] -> Text # toList :: Text -> [Item Text] #
Read Text Source #
Instance details Defined in Data.Text Methods readsPrec :: Int -> ReadS Text # readList :: ReadS [Text] # readPrec :: ReadPrec Text # readListPrec :: ReadPrec [Text] #
Show Text Source #
Instance details Defined in Data.Text.Show Methods showsPrec :: Int -> Text -> ShowS # show :: Text -> String # showList :: [Text] -> ShowS #
PrintfArg Text Source #	Since: 1.2.2.0
Instance details Defined in Data.Text Methods formatArg :: Text -> FieldFormatter # parseFormat :: Text -> ModifierParser #
Binary Text Source #	Since: 1.2.1.0
Instance details Defined in Data.Text Methods put :: Text -> Put # get :: Get Text # putList :: [Text] -> Put #
NFData Text Source #
Instance details Defined in Data.Text Methods rnf :: Text -> () #
Eq Text Source #
Instance details Defined in Data.Text Methods (==) :: Text -> Text -> Bool # (/=) :: Text -> Text -> Bool #
Ord Text Source #
Instance details Defined in Data.Text Methods compare :: Text -> Text -> Ordering # (<) :: Text -> Text -> Bool # (<=) :: Text -> Text -> Bool # (>) :: Text -> Text -> Bool # (>=) :: Text -> Text -> Bool # max :: Text -> Text -> Text # min :: Text -> Text -> Text #
Lift Text Source #	Since: 1.2.4.0
Instance details Defined in Data.Text Methods lift :: Quote m => Text -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => Text -> Code m Text #
type Item Text Source #
Instance details Defined in Data.Text type Item Text = Char

type StrictText = Text Source #

Type synonym for the strict flavour of Text.

Construction

text Source #

Arguments

:: Array	bytearray encoded as UTF-8
-> Int	offset in bytes (not in Char!), pointing to a start of UTF-8 sequence
-> Int	length in bytes (not in Char!), pointing to an end of UTF-8 sequence
-> Text

Construct a Text without invisibly pinning its byte array in memory if its length has dwindled to zero. It ensures that empty Text values are shared.

textP :: Array -> Int -> Int -> Text Source #

Deprecated: Use text instead

Safety

safe :: Char -> Char Source #

Map a Char to a Text-safe value.

Unicode Surrogate code points are not included in the set of Unicode scalar values, but are unfortunately admitted as valid Char values by Haskell. They cannot be represented in a Text. This function remaps those code points to the Unicode replacement character (U+FFFD, '�'), and leaves other code points unchanged.

Code that must be here for accessibility

empty :: Text Source #

O(1) The empty Text.

append :: Text -> Text -> Text Source #

O(n) Appends one Text to the other by copying both of them into a new Text.

Utilities

firstf :: (a -> c) -> Maybe (a, b) -> Maybe (c, b) Source #

Apply a function to the first element of an optional pair.

Checked multiplication

mul :: Int -> Int -> Int infixl 7 Source #

Checked multiplication. Calls error if the result would overflow.

mul32 :: Int32 -> Int32 -> Int32 infixl 7 Source #

Checked multiplication. Calls error if the result would overflow.

mul64 :: Int64 -> Int64 -> Int64 infixl 7 Source #

Checked multiplication. Calls error if the result would overflow.

Debugging

showText :: Text -> String Source #

A useful show-like function for debugging purposes.

Conversions

pack :: String -> Text Source #

O(n) Convert a String into a Text. Performs replacement on invalid scalar values, so unpack . pack is not id:

>>> Data.Text.unpack (pack "\55555")
"\65533"