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Language	Haskell98

Text.ParserCombinators.Poly.State

Contents

The Parser datatype
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Synopsis

newtype Parser s t a = P (s -> [t] -> Result ([t], s) a)
data Result z a
- = Success z a
- | Failure z String
- | Committed (Result z a)
runParser :: Parser s t a -> s -> [t] -> (Either String a, s, [t])
next :: Parser s t t
eof :: Parser s t ()
satisfy :: (t -> Bool) -> Parser s t t
onFail :: Parser s t a -> Parser s t a -> Parser s t a
stUpdate :: (s -> s) -> Parser s t ()
stQuery :: (s -> a) -> Parser s t a
stGet :: Parser s t s
reparse :: [t] -> Parser s t ()
module Text.ParserCombinators.Poly.Base
module Control.Applicative

The Parser datatype

newtype Parser s t a Source #

This Parser datatype is a fairly generic parsing monad with error reporting, and running state. It can be used for arbitrary token types, not just String input. (If you do not require a running state, use module Poly.Plain instead)

Constructors

P (s -> [t] -> Result ([t], s) a)

Instances

Monad (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods (>>=) :: Parser s t a -> (a -> Parser s t b) -> Parser s t b # (>>) :: Parser s t a -> Parser s t b -> Parser s t b # return :: a -> Parser s t a # fail :: String -> Parser s t a #
Functor (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods fmap :: (a -> b) -> Parser s t a -> Parser s t b # (<$) :: a -> Parser s t b -> Parser s t a #
MonadFail (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods fail :: String -> Parser s t a #
Applicative (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods pure :: a -> Parser s t a # (<>) :: Parser s t (a -> b) -> Parser s t a -> Parser s t b # liftA2 :: (a -> b -> c) -> Parser s t a -> Parser s t b -> Parser s t c # (>) :: Parser s t a -> Parser s t b -> Parser s t b # (<*) :: Parser s t a -> Parser s t b -> Parser s t a #
Alternative (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods empty :: Parser s t a # (<\|>) :: Parser s t a -> Parser s t a -> Parser s t a # some :: Parser s t a -> Parser s t [a] # many :: Parser s t a -> Parser s t [a] #
PolyParse (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser
Commitment (Parser s t) Source #
Instance details Defined in Text.ParserCombinators.Poly.StateParser Methods commit :: Parser s t a -> Parser s t a Source # adjustErr :: Parser s t a -> (String -> String) -> Parser s t a Source # oneOf' :: [(String, Parser s t a)] -> Parser s t a Source #

data Result z a Source #

A return type like Either, that distinguishes not only between right and wrong answers, but also has commitment, so that a failure cannot be undone. This should only be used for writing very primitive parsers - really it is an internal detail of the library. The z type is the remaining unconsumed input.

Constructors

Success z a
Failure z String
Committed (Result z a)

Instances

Functor (Result z) Source #
Instance details Defined in Text.ParserCombinators.Poly.Result Methods fmap :: (a -> b) -> Result z a -> Result z b # (<$) :: a -> Result z b -> Result z a #

runParser :: Parser s t a -> s -> [t] -> (Either String a, s, [t]) Source #

Apply a parser to an input token sequence.

Basic parsers

next :: Parser s t t Source #

Simply return the next token in the input tokenstream.

eof :: Parser s t () Source #

Succeed if the end of file/input has been reached, fail otherwise.

satisfy :: (t -> Bool) -> Parser s t t Source #

Return the next token if it satisfies the given predicate.

onFail :: Parser s t a -> Parser s t a -> Parser s t a infixl 6 Source #

p onFail q means parse p, unless p fails, in which case parse q instead. Can be chained together to give multiple attempts to parse something. (Note that q could itself be a failing parser, e.g. to change the error message from that defined in p to something different.) However, a severe failure in p cannot be ignored.

State-handling

stUpdate :: (s -> s) -> Parser s t () Source #

Update the internal state.

stQuery :: (s -> a) -> Parser s t a Source #

Query the internal state.

stGet :: Parser s t s Source #

Deliver the entire internal state.

Re-parsing

reparse :: [t] -> Parser s t () Source #

Push some tokens back onto the front of the input stream and reparse. This is useful e.g. for recursively expanding macros. When the user-parser recognises a macro use, it can lookup the macro expansion from the parse state, lex it, and then stuff the lexed expansion back down into the parser.

Re-export all more general combinators

module Text.ParserCombinators.Poly.Base

module Control.Applicative