polyparse-1.12: A variety of alternative parser combinator libraries.

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The Parser datatype

newtype Parser s a #

This Parser datatype is a specialised parsing monad with error reporting. Whereas the standard version can be used for arbitrary token types, this version is specialised to Text input only.


P (s -> Text -> Result (Text, s) a) 


Monad (Parser s) # 


(>>=) :: Parser s a -> (a -> Parser s b) -> Parser s b #

(>>) :: Parser s a -> Parser s b -> Parser s b #

return :: a -> Parser s a #

fail :: String -> Parser s a #

Functor (Parser s) # 


fmap :: (a -> b) -> Parser s a -> Parser s b #

(<$) :: a -> Parser s b -> Parser s a #

Applicative (Parser s) # 


pure :: a -> Parser s a #

(<*>) :: Parser s (a -> b) -> Parser s a -> Parser s b #

(*>) :: Parser s a -> Parser s b -> Parser s b #

(<*) :: Parser s a -> Parser s b -> Parser s a #

Alternative (Parser s) # 


empty :: Parser s a #

(<|>) :: Parser s a -> Parser s a -> Parser s a #

some :: Parser s a -> Parser s [a] #

many :: Parser s a -> Parser s [a] #

PolyParse (Parser s) # 
Commitment (Parser s) # 


commit :: Parser s a -> Parser s a #

adjustErr :: Parser s a -> (String -> String) -> Parser s a #

oneOf' :: [(String, Parser s a)] -> Parser s a #

data Result z a #

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.


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


Functor (Result z) # 


fmap :: (a -> b) -> Result z a -> Result z b #

(<$) :: a -> Result z b -> Result z a #

runParser :: Parser s a -> s -> Text -> (Either String a, s, Text) #

Apply a parser to an input token sequence.

Basic parsers

next :: Parser s Char #

Simply return the next token in the input tokenstream.

eof :: Parser s () #

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

satisfy :: (Char -> Bool) -> Parser s Char #

Return the next token if it satisfies the given predicate.

onFail :: Parser s a -> Parser s a -> Parser s a #

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.

Derived parsers (but implemented more efficiently)

manySatisfy :: (Char -> Bool) -> Parser s Text #

manySatisfy p is a more efficient fused version of many (satisfy p)

many1Satisfy :: (Char -> Bool) -> Parser s Text #

many1Satisfy p is a more efficient fused version of many1 (satisfy p)


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

Update the internal state.

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

Query the internal state.

stGet :: Parser s s #

Deliver the entire internal state.


reparse :: Text -> Parser s () #

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