Data.Char

Contents

Characters and strings
Character classification
- Subranges
- Unicode general categories
Case conversion
Single digit characters
Numeric representations
String representations

Synopsis

Characters and strings

A String is a list of characters. String constants in Haskell are values of type String.

Character classification

Unicode characters are divided into letters, numbers, marks, punctuation, symbols, separators (including spaces) and others (including control characters).

isLetter :: 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 Data.Char.isAlpha.

isMark :: Char -> Bool Source

Selects Unicode mark characters, e.g. accents and the like, which combine with preceding letters.

isNumber :: Char -> Bool Source

Selects Unicode numeric characters, including digits from various scripts, Roman numerals, etc.

isPunctuation :: Char -> Bool Source

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

isSymbol :: Char -> Bool Source

Selects Unicode symbol characters, including mathematical and currency symbols.

isSeparator :: Char -> Bool Source

Selects Unicode space and separator characters.

Subranges

Unicode general categories

data GeneralCategory Source

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

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

generalCategory :: Char -> GeneralCategory Source

The Unicode general category of the character.

Case conversion

toUpper

toLower

toTitle

Single digit characters

digitToInt :: Char -> Int Source

Convert a single digit Char to the corresponding Int. This function fails unless its argument satisfies isHexDigit, but recognises both upper and lower-case hexadecimal digits (i.e. '0'..'9', 'a'..'f', 'A'..'F').

intToDigit :: Int -> Char Source

Convert an Int in the range 0..15 to the corresponding single digit Char. This function fails on other inputs, and generates lower-case hexadecimal digits.

Numeric representations

ord :: Char -> Int Source

The Prelude.fromEnum method restricted to the type Data.Char.Char.

chr :: Int -> Char Source

The Prelude.toEnum method restricted to the type Data.Char.Char.

String representations

showLitChar :: Char -> ShowS Source

Convert a character to a string using only printable characters, using Haskell source-language escape conventions. For example:

 showLitChar '\n' s  =  "\\n" ++ s

lexLitChar

readLitChar