megaparsec-5.3.0: Monadic parser combinators

Copyright© 2015–2017 Megaparsec contributors
© 2007 Paolo Martini
© 1999–2001 Daan Leijen
LicenseFreeBSD
MaintainerMark Karpov <markkarpov@opmbx.org>
Stabilityexperimental
Portabilitynon-portable
Safe HaskellNone
LanguageHaskell2010

Text.Megaparsec.Char

Contents

Description

Commonly used character parsers.

Synopsis

Simple parsers

newline :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a newline character.

crlf :: (MonadParsec e s m, Token s ~ Char) => m String Source #

Parse a carriage return character followed by a newline character. Return sequence of characters parsed.

eol :: (MonadParsec e s m, Token s ~ Char) => m String Source #

Parse a CRLF (see crlf) or LF (see newline) end of line. Return the sequence of characters parsed.

eol = (pure <$> newline) <|> crlf

tab :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a tab character.

space :: (MonadParsec e s m, Token s ~ Char) => m () Source #

Skip zero or more white space characters.

See also: skipMany and spaceChar.

Categories of characters

controlChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a control character (a non-printing character of the Latin-1 subset of Unicode).

spaceChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode space character, and the control characters: tab, newline, carriage return, form feed, and vertical tab.

upperChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse an upper-case or title-case alphabetic Unicode character. Title case is used by a small number of letter ligatures like the single-character form of Lj.

lowerChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a lower-case alphabetic Unicode character.

letterChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse an alphabetic Unicode character: lower-case, upper-case, or title-case letter, or a letter of case-less scripts/modifier letter.

alphaNumChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse an alphabetic or numeric digit Unicode characters.

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

printChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a printable Unicode character: letter, number, mark, punctuation, symbol or space.

digitChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse an ASCII digit, i.e between “0” and “9”.

octDigitChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse an octal digit, i.e. between “0” and “7”.

hexDigitChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a hexadecimal digit, i.e. between “0” and “9”, or “a” and “f”, or “A” and “F”.

markChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode mark character (accents and the like), which combines with preceding characters.

numberChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode numeric character, including digits from various scripts, Roman numerals, etc.

punctuationChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode punctuation character, including various kinds of connectors, brackets and quotes.

symbolChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode symbol characters, including mathematical and currency symbols.

separatorChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a Unicode space and separator characters.

asciiChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

Parse a character from the first 128 characters of the Unicode character set, corresponding to the ASCII character set.

latin1Char :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

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

charCategory :: (MonadParsec e s m, Token s ~ Char) => GeneralCategory -> m Char Source #

charCategory cat parses character in Unicode General Category cat, see GeneralCategory.

categoryName :: GeneralCategory -> String Source #

Return human-readable name of Unicode General Category.

More general parsers

char :: (MonadParsec e s m, Token s ~ Char) => Char -> m Char Source #

char c parses a single character c.

semicolon = char ';'

char' :: (MonadParsec e s m, Token s ~ Char) => Char -> m Char Source #

The same as char but case-insensitive. This parser returns actually parsed character preserving its case.

>>> parseTest (char' 'e') "E"
'E'
>>> parseTest (char' 'e') "G"
1:1:
unexpected 'G'
expecting 'E' or 'e'

anyChar :: (MonadParsec e s m, Token s ~ Char) => m Char Source #

This parser succeeds for any character. Returns the parsed character.

oneOf :: (Foldable f, MonadParsec e s m, Token s ~ Char) => f Char -> m Char Source #

oneOf cs succeeds if the current character is in the supplied collection of characters cs. Returns the parsed character. Note that this parser doesn't automatically generate “expected” component of error message, so usually you should label it manually with label or (<?>).

See also: satisfy.

digit = oneOf ['0'..'9'] <?> "digit"

oneOf' :: (Foldable f, MonadParsec e s m, Token s ~ Char) => f Char -> m Char Source #

The same as oneOf, but case-insensitive. Returns the parsed character preserving its case.

vowel = oneOf' "aeiou" <?> "vowel"

noneOf :: (Foldable f, MonadParsec e s m, Token s ~ Char) => f Char -> m Char Source #

As the dual of oneOf, noneOf cs succeeds if the current character not in the supplied list of characters cs. Returns the parsed character.

noneOf' :: (Foldable f, MonadParsec e s m, Token s ~ Char) => f Char -> m Char Source #

The same as noneOf, but case-insensitive.

consonant = noneOf' "aeiou" <?> "consonant"

satisfy :: (MonadParsec e s m, Token s ~ Char) => (Char -> Bool) -> m Char Source #

The parser satisfy f succeeds for any character for which the supplied function f returns True. Returns the character that is actually parsed.

digitChar = satisfy isDigit <?> "digit"
oneOf cs  = satisfy (`elem` cs)

Sequence of characters

string :: (MonadParsec e s m, Token s ~ Char) => String -> m String Source #

string s parses a sequence of characters given by s. Returns the parsed string (i.e. s).

divOrMod = string "div" <|> string "mod"

string' :: (MonadParsec e s m, Token s ~ Char) => String -> m String Source #

The same as string, but case-insensitive. On success returns string cased as actually parsed input.

>>> parseTest (string' "foobar") "foObAr"
"foObAr"