haskell98-2.0.0.3: Compatibility with Haskell 98

Safe HaskellSafe
LanguageHaskell98

Char

Synopsis

Documentation

isAscii :: Char -> Bool

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

isLatin1 :: Char -> Bool

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

isControl :: Char -> Bool

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

isPrint :: Char -> Bool

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

isSpace :: Char -> Bool

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

isUpper :: Char -> Bool

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

Selects lower-case alphabetic Unicode characters (letters).

isAlpha :: Char -> Bool

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

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

isOctDigit :: Char -> Bool

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

isHexDigit :: Char -> Bool

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

isAlphaNum :: Char -> Bool

Selects alphabetic or numeric digit Unicode characters.

Note that numeric digits outside the ASCII range are selected by this function but not by isDigit. Such digits may be part of identifiers but are not used by the printer and reader to represent numbers.

digitToInt :: Char -> Int

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

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.

toUpper :: Char -> Char

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

toLower :: Char -> Char

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

ord :: Char -> Int

The fromEnum method restricted to the type Char.

chr :: Int -> Char

The toEnum method restricted to the type Char.

readLitChar :: ReadS Char

Read a string representation of a character, using Haskell source-language escape conventions, and convert it to the character that it encodes. For example:

readLitChar "\\nHello"  =  [('\n', "Hello")]

showLitChar :: Char -> ShowS

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

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

lexLitChar :: ReadS String

Read a string representation of a character, using Haskell source-language escape conventions. For example:

lexLitChar  "\\nHello"  =  [("\\n", "Hello")]

data Char :: *

The character type Char is an enumeration whose values represent Unicode (or equivalently ISO/IEC 10646) characters (see http://www.unicode.org/ for details). This set extends the ISO 8859-1 (Latin-1) character set (the first 256 characters), which is itself an extension of the ASCII character set (the first 128 characters). A character literal in Haskell has type Char.

To convert a Char to or from the corresponding Int value defined by Unicode, use toEnum and fromEnum from the Enum class respectively (or equivalently ord and chr).

type String = [Char]

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