polyparse Source code Contents Index

Text.ParserCombinators.Poly.State

Contents The Parser datatype basic parsers State-handling Re-parsing Re-export all more general combinators.

Synopsis

newtype Parser s t a = P (s -> [t] -> (EitherE String a, s, [t])) runParser :: Parser s t a -> s -> [t] -> (Either String a, s, [t]) satisfy :: (t -> Bool) -> Parser s t t 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

The Parser datatype

newtype Parser s t a Source

The Parser datatype is a fairly generic parsing monad with error reporting and a running state. It can be used for arbitrary token types, not just String input. Constructors P (s -> [t] -> (EitherE String a, s, [t])) Instances Functor (Parser s t) Monad (Parser s t) PolyParse (Parser s t)

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

Apply a parser to an initial state and input token sequence.

basic parsers

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

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

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