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/Haskell 8

Data.Text.Internal

Copyright (c) 2008 2009 Tom Harper
(c) 2009 2010 Bryan O'Sullivan
(c) 2009 Duncan Coutts
License BSD-style
Maintainer [email protected]
Stability experimental
Portability GHC
Safe Haskell None
Language Haskell98

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!

Types

Internally, the Text type is represented as an array of Word16 UTF-16 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-16 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, '�').
  • A leading (or "high") surrogate code unit (0xD800–0xDBFF) must always be followed by a trailing (or "low") surrogate code unit (0xDC00-0xDFFF). A trailing surrogate code unit must always be preceded by a leading surrogate code unit.

data Text Source

A space efficient, packed, unboxed Unicode text type.

Constructors

Text !Array !Int !Int
Instances
IsList Text

Since: text-1.2.0.0

Instance details

Defined in Data.Text

Associated Types

type Item Text :: Type Source

Eq Text
Instance details

Defined in Data.Text

Methods

(==) :: Text -> Text -> Bool Source

(/=) :: Text -> Text -> Bool Source

Data Text

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 Source

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Text Source

toConstr :: Text -> Constr Source

dataTypeOf :: Text -> DataType Source

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Text) Source

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Text) Source

gmapT :: (forall b. Data b => b -> b) -> Text -> Text Source

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Text -> r Source

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Text -> r Source

gmapQ :: (forall d. Data d => d -> u) -> Text -> [u] Source

gmapQi :: Int -> (forall d. Data d => d -> u) -> Text -> u Source

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Text -> m Text Source

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Text -> m Text Source

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Text -> m Text Source

Ord Text
Instance details

Defined in Data.Text

Methods

compare :: Text -> Text -> Ordering Source

(<) :: Text -> Text -> Bool Source

(<=) :: Text -> Text -> Bool Source

(>) :: Text -> Text -> Bool Source

(>=) :: Text -> Text -> Bool Source

max :: Text -> Text -> Text Source

min :: Text -> Text -> Text Source

Read Text
Instance details

Defined in Data.Text

Show Text
Instance details

Defined in Data.Text.Show

IsString Text
Instance details

Defined in Data.Text

Methods

fromString :: String -> Text Source

Semigroup Text

Non-orphan Semigroup instance only defined for base-4.9.0.0 and later; orphan instances for older GHCs are provided by the semigroups package

Since: text-1.2.2.0

Instance details

Defined in Data.Text

Methods

(<>) :: Text -> Text -> Text Source

sconcat :: NonEmpty Text -> Text Source

stimes :: Integral b => b -> Text -> Text Source

Monoid Text
Instance details

Defined in Data.Text

PrintfArg Text

Only defined for base-4.7.0.0 and later

Since: text-1.2.2.0

Instance details

Defined in Data.Text

Binary Text

Since: text-1.2.1.0

Instance details

Defined in Data.Text

Methods

put :: Text -> Put Source

get :: Get Text Source

putList :: [Text] -> Put Source

NFData Text
Instance details

Defined in Data.Text

Methods

rnf :: Text -> () Source

type Item Text
Instance details

Defined in Data.Text

type Item Text = Char

Construction

text :: Array -> Int -> Int -> Text Source

Construct a Text without invisibly pinning its byte array in memory if its length has dwindled to zero.

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

Deprecated: Use text instead

Safety

safe :: Char -> Char Source

Map a Char to a Text-safe value.

UTF-16 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.

empty_ :: Text Source

A non-inlined version of empty.

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.

© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.6.1/docs/html/libraries/text-1.2.3.1/Data-Text-Internal.html