{- 
    Copyright 2010-2015 Mario Blazevic

    This file is part of the Streaming Component Combinators (SCC) project.

    The SCC project is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
    License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later
    version.

    SCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
    of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along with SCC.  If not, see
    <http://www.gnu.org/licenses/>.
-}

-- | This module defines parsing combinators for incremental parsers with symmetric choice.
-- 
-- The exported 'Parser' type can provide partial parsing results from partial input, as long as the output is a
-- 'Monoid'. Construct a parser using the primitives and combinators, supply it with input using functions 'feed' and
-- 'feedEof', and extract the parsed output using 'results'.
-- 
-- Implementation is based on Brzozowski derivatives.

{-# LANGUAGE EmptyDataDecls, FlexibleInstances #-}

module Text.ParserCombinators.Incremental.Symmetric (
   module Text.ParserCombinators.Incremental,
   Parser, Symmetric, allOf
)
where

import Control.Applicative (Alternative (empty, (<|>)), many, some)
import Control.Monad (MonadPlus (mzero, mplus))
import Data.Monoid (Monoid)

import Text.ParserCombinators.Incremental hiding (Parser)
import qualified Text.ParserCombinators.Incremental as Incremental (Parser)

-- | An empty type to specialize 'Parser' for the symmetric 'Alternative' instance.
data Symmetric

type Parser = Incremental.Parser Symmetric

-- | The symmetric version of the '<|>' choice combinator.
instance Monoid s => Alternative (Incremental.Parser Symmetric s) where
   empty :: Parser Symmetric s a
empty = Parser Symmetric s a
forall t s r. Parser t s r
failure
   Parser Symmetric s a
p1 <|> :: Parser Symmetric s a
-> Parser Symmetric s a -> Parser Symmetric s a
<|> Parser Symmetric s a
p2 = Parser Symmetric s a
p1 Parser Symmetric s a
-> Parser Symmetric s a -> Parser Symmetric s a
forall t s r. Parser t s r -> Parser t s r -> Parser t s r
<||> Parser Symmetric s a
p2
   many :: Parser Symmetric s a -> Parser Symmetric s [a]
many = Parser Symmetric s a -> Parser Symmetric s [a]
forall s t r.
(Monoid s, Alternative (Parser t s)) =>
Parser t s r -> Parser t s [r]
defaultMany
   some :: Parser Symmetric s a -> Parser Symmetric s [a]
some = Parser Symmetric s a -> Parser Symmetric s [a]
forall s t r.
(Monoid s, Alternative (Parser t s)) =>
Parser t s r -> Parser t s [r]
defaultSome

-- | The 'MonadPlus' instances are the same as the 'Alternative' instances.
instance Monoid s => MonadPlus (Incremental.Parser Symmetric s) where
   mzero :: Parser Symmetric s a
mzero = Parser Symmetric s a
forall t s r. Parser t s r
failure
   mplus :: Parser Symmetric s a
-> Parser Symmetric s a -> Parser Symmetric s a
mplus = Parser Symmetric s a
-> Parser Symmetric s a -> Parser Symmetric s a
forall (f :: * -> *) a. Alternative f => f a -> f a -> f a
(<|>)

allOf :: Parser s r -> Incremental.Parser a s r
allOf :: Parser s r -> Parser a s r
allOf Parser s r
p = (forall a. Parser Symmetric s a -> Parser a s a)
-> Parser s r -> Parser a s r
forall t s b r.
(forall a. Parser t s a -> Parser b s a)
-> Parser t s r -> Parser b s r
mapType forall a. Parser Symmetric s a -> Parser a s a
forall s r a. Parser s r -> Parser a s r
allOf Parser s r
p