GHC.Unicode

base-4.13.0.0: Basic libraries

Copyright | (c) The University of Glasgow 2003
License | see libraries/base/LICENSE
Maintainer | cvs-ghc@haskell.org
Stability | internal
Portability | non-portable (GHC extensions)
Safe Haskell | Trustworthy
Language | Haskell2010

GHC.Unicode

Description

Implementations for the character predicates (isLower, isUpper, etc.) and the conversions (toUpper, toLower). The implementation uses libunicode on Unix systems if that is available.

Synopsis

- data GeneralCategory
  - = UppercaseLetter
  - | LowercaseLetter
  - | TitlecaseLetter
  - | ModifierLetter
  - | OtherLetter
  - | NonSpacingMark
  - | SpacingCombiningMark
  - | EnclosingMark
  - | DecimalNumber
  - | LetterNumber
  - | OtherNumber
  - | ConnectorPunctuation
  - | DashPunctuation
  - | OpenPunctuation
  - | ClosePunctuation
  - | InitialQuote
  - | FinalQuote
  - | OtherPunctuation
  - | MathSymbol
  - | CurrencySymbol
  - | ModifierSymbol
  - | OtherSymbol
  - | Space
  - | LineSeparator
  - | ParagraphSeparator
  - | Control
  - | Format
  - | Surrogate
  - | PrivateUse
  - | NotAssigned
- generalCategory :: Char -> GeneralCategory
- isAscii :: Char -> Bool
- isLatin1 :: Char -> Bool
- isControl :: Char -> Bool
- isAsciiUpper :: Char -> Bool
- isAsciiLower :: Char -> Bool
- isPrint :: Char -> Bool
- isSpace :: Char -> Bool
- isUpper :: Char -> Bool
- isLower :: Char -> Bool
- isAlpha :: Char -> Bool
- isDigit :: Char -> Bool
- isOctDigit :: Char -> Bool
- isHexDigit :: Char -> Bool
- isAlphaNum :: Char -> Bool
- isPunctuation :: Char -> Bool
- isSymbol :: Char -> Bool
- toUpper :: Char -> Char
- toLower :: Char -> Char
- toTitle :: Char -> Char
- wgencat :: Int -> Int

# Documentation

data GeneralCategory Source #

Unicode General Categories (column 2 of the UnicodeData table) in the order they are listed in the Unicode standard (the Unicode Character Database, in particular).

#### Examples

Expand

Basic usage:

    >>> :t OtherLetter
    OtherLetter :: GeneralCategory

`Eq` instance:

    >>> UppercaseLetter == UppercaseLetter
    True
    >>> UppercaseLetter == LowercaseLetter
    False

`Ord` instance:

    >>> NonSpacingMark <= MathSymbol
    True

`Enum` instance:

    >>> enumFromTo ModifierLetter SpacingCombiningMark
    [ModifierLetter,OtherLetter,NonSpacingMark,SpacingCombiningMark]

`Read` instance:

    >>> read "DashPunctuation" :: GeneralCategory
    DashPunctuation
    >>> read "17" :: GeneralCategory
    *** Exception: Prelude.read: no parse

`Show` instance:

    >>> show EnclosingMark
    "EnclosingMark"

`Bounded` instance:

    >>> minBound :: GeneralCategory
    UppercaseLetter
    >>> maxBound :: GeneralCategory
    NotAssigned

`Ix` instance:

    >>> import Data.Ix ( index )
    >>> index (OtherLetter,Control) FinalQuote
    12
    >>> index (OtherLetter,Control) Format
    *** Exception: Error in array index

Constructors

UppercaseLetter | Lu: Letter, Uppercase
LowercaseLetter | Ll: Letter, Lowercase
TitlecaseLetter | Lt: Letter, Titlecase
ModifierLetter | Lm: Letter, Modifier
OtherLetter | Lo: Letter, Other
NonSpacingMark | Mn: Mark, Non-Spacing
SpacingCombiningMark | Mc: Mark, Spacing Combining
EnclosingMark | Me: Mark, Enclosing
DecimalNumber | Nd: Number, Decimal
LetterNumber | Nl: Number, Letter
OtherNumber | No: Number, Other
ConnectorPunctuation | Pc: Punctuation, Connector
DashPunctuation | Pd: Punctuation, Dash
OpenPunctuation | Ps: Punctuation, Open
ClosePunctuation | Pe: Punctuation, Close
InitialQuote | Pi: Punctuation, Initial quote
FinalQuote | Pf: Punctuation, Final quote
OtherPunctuation | Po: Punctuation, Other
MathSymbol | Sm: Symbol, Math
CurrencySymbol | Sc: Symbol, Currency
ModifierSymbol | Sk: Symbol, Modifier
OtherSymbol | So: Symbol, Other
Space | Zs: Separator, Space
LineSeparator | Zl: Separator, Line
ParagraphSeparator | Zp: Separator, Paragraph
Control | Cc: Other, Control
Format | Cf: Other, Format
Surrogate | Cs: Other, Surrogate
PrivateUse | Co: Other, Private Use
NotAssigned | Cn: Other, Not Assigned

#### Instances

Instances details

Bounded GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods minBound :: GeneralCategory Source # maxBound :: GeneralCategory Source #
Enum GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods succ :: GeneralCategory -> GeneralCategory Source # pred :: GeneralCategory -> GeneralCategory Source # toEnum :: Int -> GeneralCategory Source # fromEnum :: GeneralCategory -> Int Source # enumFrom :: GeneralCategory -> [GeneralCategory] Source # enumFromThen :: GeneralCategory -> GeneralCategory -> [GeneralCategory] Source # enumFromTo :: GeneralCategory -> GeneralCategory -> [GeneralCategory] Source # enumFromThenTo :: GeneralCategory -> GeneralCategory -> GeneralCategory -> [GeneralCategory] Source #
Eq GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods (==) :: GeneralCategory -> GeneralCategory -> Bool Source # (/=) :: GeneralCategory -> GeneralCategory -> Bool Source #
Ord GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods compare :: GeneralCategory -> GeneralCategory -> Ordering Source # (<) :: GeneralCategory -> GeneralCategory -> Bool Source # (<=) :: GeneralCategory -> GeneralCategory -> Bool Source # (>) :: GeneralCategory -> GeneralCategory -> Bool Source # (>=) :: GeneralCategory -> GeneralCategory -> Bool Source # max :: GeneralCategory -> GeneralCategory -> GeneralCategory Source # min :: GeneralCategory -> GeneralCategory -> GeneralCategory Source #
Read GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Read Methods readsPrec :: Int -> ReadS GeneralCategory Source # readList :: ReadS [GeneralCategory] Source # readPrec :: ReadPrec GeneralCategory Source # readListPrec :: ReadPrec [GeneralCategory] Source #
Show GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods showsPrec :: Int -> GeneralCategory -> ShowS Source # show :: GeneralCategory -> String Source # showList :: [GeneralCategory] -> ShowS Source #
Ix GeneralCategory # | Since: base-2.1
Instance details Defined in GHC.Unicode Methods range :: (GeneralCategory, GeneralCategory) -> [GeneralCategory] Source # index :: (GeneralCategory, GeneralCategory) -> GeneralCategory -> Int Source # unsafeIndex :: (GeneralCategory, GeneralCategory) -> GeneralCategory -> Int Source # inRange :: (GeneralCategory, GeneralCategory) -> GeneralCategory -> Bool Source # rangeSize :: (GeneralCategory, GeneralCategory) -> Int Source # unsafeRangeSize :: (GeneralCategory, GeneralCategory) -> Int Source #

generalCategory :: Char -> GeneralCategory Source #

The Unicode general category of the character. This relies on the `Enum` instance of `GeneralCategory`, which must remain in the same order as the categories are presented in the Unicode standard.

#### Examples

Expand

Basic usage:

    >>> generalCategory 'a'
    LowercaseLetter
    >>> generalCategory 'A'
    UppercaseLetter
    >>> generalCategory '0'
    DecimalNumber
    >>> generalCategory '%'
    OtherPunctuation
    >>> generalCategory '♥'
    OtherSymbol
    >>> generalCategory '\31'
    Control
    >>> generalCategory ' '
    Space

isAscii :: Char -> Bool Source #

Selects the first 128 characters of the Unicode character set, corresponding to the ASCII character set.

isLatin1 :: Char -> Bool Source #

Selects the first 256 characters of the Unicode character set, corresponding to the ISO 8859-1 (Latin-1) character set.

isControl :: Char -> Bool Source #

Selects control characters, which are the non-printing characters of the Latin-1 subset of Unicode.

isAsciiUpper :: Char -> Bool Source #

Selects ASCII upper-case letters, i.e. characters satisfying both `isAscii` and `isUpper`.

isAsciiLower :: Char -> Bool Source #

Selects ASCII lower-case letters, i.e. characters satisfying both `isAscii` and `isLower`.

isPrint :: Char -> Bool Source #

Selects printable Unicode characters (letters, numbers, marks, punctuation, symbols and spaces).

isSpace :: Char -> Bool Source #

Returns `True` for any Unicode space character, and the control characters `\t`, `\n`, `\r`, `\f`, `\v`.

isUpper :: Char -> Bool Source #

Selects upper-case or title-case alphabetic Unicode characters (letters). Title case is used by a small number of letter ligatures like the single-character form of Lj.

isLower :: Char -> Bool Source #

Selects lower-case alphabetic Unicode characters (letters).

isAlpha :: Char -> Bool Source #

Selects alphabetic Unicode characters (lower-case, upper-case and title-case letters, plus letters of caseless scripts and modifiers letters). This function is equivalent to `isLetter`.

isDigit :: Char -> Bool Source #

Selects ASCII digits, i.e. `'0'`..`'9'`.

isOctDigit :: Char -> Bool Source #

Selects ASCII octal digits, i.e. `'0'`..`'7'`.

isHexDigit :: Char -> Bool Source #

Selects ASCII hexadecimal digits, i.e. `'0'`..`'9'`, `'a'`..`'f'`, `'A'`..`'F'`.

isAlphaNum :: Char -> Bool Source #

Selects alphabetic or numeric Unicode characters.

Note that numeric digits outside the ASCII range, as well as numeric characters which aren't digits, are selected by this function but not by `isDigit`. Such characters may be part of identifiers but are not used by the printer and reader to represent numbers.

isPunctuation :: Char -> Bool Source #

Selects Unicode punctuation characters, including various kinds of connectors, brackets and quotes.

This function returns `True` if its argument has one of the following `GeneralCategory`s, or `False` otherwise:

- `ConnectorPunctuation`
- `DashPunctuation`
- `OpenPunctuation`
- `ClosePunctuation`
- `InitialQuote`
- `FinalQuote`
- `OtherPunctuation`

These classes are defined in the Unicode Character Database, part of the Unicode standard. The same document defines what is and is not a "Punctuation".

#### Examples

Expand

Basic usage:

    >>> isPunctuation 'a'
    False
    >>> isPunctuation '7'
    False
    >>> isPunctuation '♥'
    False
    >>> isPunctuation '"'
    True
    >>> isPunctuation '?'
    True
    >>> isPunctuation '—'
    True

isSymbol :: Char -> Bool Source #

Selects Unicode symbol characters, including mathematical and currency symbols.

This function returns `True` if its argument has one of the following `GeneralCategory`s, or `False` otherwise:

- `MathSymbol`
- `CurrencySymbol`
- `ModifierSymbol`
- `OtherSymbol`

These classes are defined in the Unicode Character Database, part of the Unicode standard. The same document defines what is and is not a "Symbol".

#### Examples

Expand

Basic usage:

    >>> isSymbol 'a'
    False
    >>> isSymbol '6'
    False
    >>> isSymbol '='
    True

The definition of "math symbol" may be a little counter-intuitive depending on one's background:

    >>> isSymbol '+'
    True
    >>> isSymbol '-'
    False

toUpper :: Char -> Char Source #

Convert a letter to the corresponding upper-case letter, if any. Any other character is returned unchanged.

toLower :: Char -> Char Source #

Convert a letter to the corresponding lower-case letter, if any. Any other character is returned unchanged.

toTitle :: Char -> Char Source #

Convert a letter to the corresponding title-case or upper-case letter, if any. (Title case differs from upper case only for a small number of ligature letters.) Any other character is returned unchanged.

wgencat :: Int -> Int Source #