text-0.11.1.5: An efficient packed Unicode text type.

Portability | GHC
Stability | experimental
Maintainer | bos@serpentine.com, rtomharper@googlemail.com, duncan@haskell.org

Data.Text.Internal

Contents

- Types
- Construction
- Safety
- Code that must be here for accessibility
- Utilities
- Debugging

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
- text :: Array -> Int -> Int -> Text
- textP :: Array -> Int -> Int -> Text
- safe :: Char -> Char
- empty :: Text
- firstf :: (a -> c) -> Maybe (a, b) -> Maybe (c, b)
- showText :: Text -> String

# Types

data Text

A space efficient, packed, unboxed Unicode text type.

Constructors

Text !Array !Int !Int |

Instances

Eq Text |
Data Text |
Ord Text |
Read Text |
Show Text |
Typeable Text |
IsString Text |
Monoid Text |
NFData Text |

# Construction

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

Smart constructor.

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

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

# Safety

safe :: Char -> Char

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 "�", and leaves other code points unchanged.

# Code that must be here for accessibility

empty :: Text

O(1) The empty `Text`.

# Utilities

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

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

# Debugging

showText :: Text -> String

A useful `show`-like function for debugging purposes.