Copyright | (c) The University of Glasgow 2003 |
---|---|
License | see libraries/base/LICENSE |
Maintainer | [email protected] |
Stability | internal |
Portability | non-portable (GHC extensions) |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Implementations for the character predicates (isLower, isUpper, etc.) and the conversions (toUpper, toLower). The implementation uses libunicode on Unix systems if that is available.
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).
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
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 |
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.
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".
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:
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".
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.
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.8.3/docs/html/libraries/base-4.13.0.0/GHC-Unicode.html