| Safe Haskell | Safe-Infered |
|---|
Text.ParserCombinators.Poly.StateText
Contents
- newtype Parser s a = P (s -> Text -> Result (Text, s) a)
- data Result z a
- runParser :: Parser s a -> s -> Text -> (Either String a, s, Text)
- next :: Parser s Char
- eof :: Parser s ()
- satisfy :: (Char -> Bool) -> Parser s Char
- onFail :: Parser s a -> Parser s a -> Parser s a
- manySatisfy :: (Char -> Bool) -> Parser s Text
- many1Satisfy :: (Char -> Bool) -> Parser s Text
- stUpdate :: (s -> s) -> Parser s ()
- stQuery :: (s -> a) -> Parser s a
- stGet :: Parser s s
- reparse :: Text -> Parser s ()
- module Text.ParserCombinators.Poly.Base
- module Control.Applicative
The Parser datatype
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.
Instances
| Monad (Parser s) | |
| Functor (Parser s) | |
| Applicative (Parser s) | |
| Alternative (Parser s) | |
| PolyParse (Parser s) | |
| Commitment (Parser s) |
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.
runParser :: Parser s a -> s -> Text -> (Either String a, s, Text)Source
Apply a parser to an input token sequence.
Basic parsers
satisfy :: (Char -> Bool) -> Parser s CharSource
Return the next token if it satisfies the given predicate.
onFail :: Parser s a -> Parser s a -> Parser s aSource
p 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.
onFail q
Derived parsers (but implemented more efficiently)
manySatisfy :: (Char -> Bool) -> Parser s TextSource
manySatisfy p is a more efficient fused version of many (satisfy p)
many1Satisfy :: (Char -> Bool) -> Parser s TextSource
many1Satisfy p is a more efficient fused version of many1 (satisfy p)
State-handling
Re-parsing
reparse :: Text -> Parser s ()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 Control.Applicative