polyparse-1.4.1: A variety of alternative parser combinator libraries.

Text.ParserCombinators.Poly.Plain

Contents

Synopsis

The Parser datatype

newtype Parser t a Source

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

Constructors

P ([t] -> Result [t] a) 

Instances

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.

Constructors

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

Instances

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

Apply a parser to an input token sequence.

basic parsers

satisfy :: (t -> Bool) -> Parser t tSource

re-parsing

reparse :: [t] -> Parser 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