A synonym for Parser Char, i.e. string input (no state)
Modulepolyparse-1.13Haskell98
Text.Parse
- 1 type
- 1 class
- 20 values
- Packagepolyparse-1.13
- Exports22
- LanguageHaskell98
- LicenceLicenseRef-LGPL
- SourceParse.hs
The Parse class is a replacement for the standard Read class.
5 declarationsThe Parse class is a replacement for the standard Read class. It is a specialisation of the (poly) Parser monad for String input. There are instances defined for all Prelude types. For user-defined types, you can write your own instance, or use DrIFT to generate them automatically, e.g. {-! derive : Parse !-}
The class Parse is a replacement for Read, operating over String input.
Essentially, it permits better error messages for why something failed to
parse. It is rather important that parse can read back exactly what
is generated by the corresponding instance of show. To apply a parser
to some text, use runParser.
Methods
parse :: TextParser aA straightforward parser for an item. (A minimal definition of a class instance requires either |parse| or |parsePrec|.)
parsePrec :: Int -> TextParser aA straightforward parser for an item, given the precedence of any surrounding expression. (Precedence determines whether parentheses are mandatory or optional.)
parseList :: TextParser [a]Parsing a list of items by default accepts the [] and comma syntax, except when the list is really a character string using "".
Instances13Parse, …
Parse IntegerDefined in polyparse-1.13 · Text.ParseParse BoolDefined in polyparse-1.13 · Text.ParseParse CharDefined in polyparse-1.13 · Text.ParseParse DoubleDefined in polyparse-1.13 · Text.ParseParse FloatDefined in polyparse-1.13 · Text.ParseParse IntDefined in polyparse-1.13 · Text.ParseParse OrderingDefined in polyparse-1.13 · Text.ParseParse ()Defined in polyparse-1.13 · Text.ParseParse a => Parse (Maybe a)Defined in polyparse-1.13 · Text.ParseParse a => Parse [a]Defined in polyparse-1.13 · Text.Parse(Parse a, Parse b) => Parse (Either a b)Defined in polyparse-1.13 · Text.Parse(Parse a, Parse b) => Parse (a, b)Defined in polyparse-1.13 · Text.Parse(Parse a, Parse b, Parse c) => Parse (a, b, c)Defined in polyparse-1.13 · Text.Parse
If there already exists a Read instance for a type, then we can make a Parser for it, but with only poor error-reporting. The string argument is the expected type or value (for error-reporting only).
If you have a TextParser for a type, you can easily make it into a Read instance, by throwing away any error messages.
If you have a TextParser for a type, you can easily make it into a Read instance, by throwing away any error messages.
Combinators specific to string input, lexed haskell-style
One lexical chunk. This is Haskell'98-style lexing - the result should match Prelude.lex apart from better error-reporting.
Ensure that the next input word is the given string. (Note the input is lexed as haskell, so wordbreaks at spaces, symbols, etc.)
Ensure that the next input word is the given string. (No lexing, so mixed spaces, symbols, are accepted.)
Allow nested parens around an item.
Allow nested parens around an item (one set required when Bool is True).
Deal with named field syntax. The string argument is the field name, and the parser returns the value of the field.
Parse one of a bunch of alternative constructors. In the list argument, the first element of the pair is the constructor name, and the second is the parser for the rest of the value. The first matching parse is returned.
Parse one of the given nullary constructors (an enumeration). The string argument is the name of the type, and the list argument should contain all of the possible enumeration values.
Parsers for literal numerics and characters
Parse a Haskell character literal, excluding the surrounding single quotes.
Parse a Haskell character literal, including the surrounding single quotes.
Re-export all the more general combinators from Poly too
module Text.ParserCombinators.Poly
Strings as whole entities
Simply return the entire remaining input String.