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|
--
-- MTLParse.hs
--
-- Author: Yoshikuni Jujo <PAF01143@nifty.ne.jp>
--
-- This file is part of mtlparse library
--
-- mtlparse is free software: you can redistribute it and/or modify
-- it under the terms of the GNU Lesser General Public License as
-- published by the Free Software Foundation, either version 3 of the
-- License, or any later version.
--
-- mtlparse is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANGY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU Lesser General Public License for more details.
--
-- You should have received a copy of the GNU Lesser General Public
-- License along with this program. If not, see
-- <http://www.gnu.org/licenses/>.
module Text.ParserCombinators.MTLParse (
module Text.ParserCombinators.MTLParse.MTLParseCore
, tokens
, tokensBack
, build
, repeatParse
, optional
, list
, neList
, greedyRepeatParse
, greedyOptional
, greedyList
, greedyNeList
, beginningOfInput
, endOfInput
, apply2M
, (>++>)
, (>:>)
) where
import Text.ParserCombinators.MTLParse.MTLParseCore
import Control.Monad( replicateM )
tokens, tokensBack :: ( Eq a, MonadParse a m ) => [ a ] -> m [ a ]
tokens = foldr ( (>:>).token ) $ return []
tokensBack = foldr ( (>:>).tokenBack ) $ return []
build :: Monad m => m a -> ( a -> b ) -> m b
build = flip liftM
repeatParse, greedyRepeatParse ::
MonadPlus m => Int -> Maybe Int -> m b -> m [ b ]
repeatParse mn ( Just mx ) p
| mn == mx = replicateM mn p
| mn < mx = replicateM mn p
`mplus`
( p >:> repeatParse mn (Just $ mx - 1) p )
| otherwise = error "minimal larger than maximal"
repeatParse mn Nothing p
= replicateM mn p
`mplus`
( p >:> repeatParse mn Nothing p )
greedyRepeatParse mn ( Just mx ) p
| mn == mx = replicateM mn p
| mn < mx = ( p >:> greedyRepeatParse mn (Just $ mx - 1) p )
`mplus`
replicateM mn p
| otherwise = error "minimal larger than maximal"
greedyRepeatParse mn Nothing p
= ( p >:> greedyRepeatParse mn Nothing p )
`mplus`
replicateM mn p
optional, greedyOptional, list, greedyList, neList, greedyNeList
:: MonadPlus m => m a -> m [ a ]
optional = repeatParse 0 $ Just 1
greedyOptional = greedyRepeatParse 0 $ Just 1
list = repeatParse 0 Nothing
greedyList = greedyRepeatParse 0 Nothing
neList = repeatParse 1 Nothing
greedyNeList = greedyRepeatParse 1 Nothing
-- beginning and end of input
beginningOfInput, endOfInput
:: ( MonadPlus m, MonadParse a m ) => b -> m b
beginningOfInput x = do ( pre, _ ) <- getHere
if null pre then return x
else mzero
endOfInput x = do ( _, post ) <- getHere
if null post then return x
else mzero
-- some tools for monad returning list
apply2M :: Monad m => ( a -> b -> c ) -> m a -> m b -> m c
apply2M op m1 m2 = do { r1 <- m1; r2 <- m2; return $ r1 `op` r2 }
(>++>) :: Monad m => m [a] -> m [a] -> m [a]
(>++>) = apply2M (++)
(>:>) :: Monad m => m a -> m [a] -> m [a]
(>:>) = apply2M (:)
|
