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module NestingXML where
import Data.Conduit
import Data.XML.Types
import Control.Monad.State
-- import qualified Text.XML.Stream.Parse as Parse (content)
type NestingXML o m a = StateT Int (ConduitM Event o m) a
runNestingXML :: NestingXML o m a -> Int -> ConduitM Event o m (a,Int)
runNestingXML = runStateT
doNestingXML :: Monad m => NestingXML o m a -> ConduitM Event o m a
doNestingXML = fmap fst . flip runNestingXML 0
nesting :: Monad m => NestingXML o m Int
nesting = get
awaitXML :: Monad m => NestingXML o m (Maybe Event)
awaitXML = do
lvl <- get
xml <- lift await
put $case xml of
Just (EventBeginElement _ _) -> lvl+1
Just (EventEndElement _) -> lvl-1
_ -> lvl
return xml
withXML
:: Monad m => (Event -> NestingXML o m ()) -> NestingXML o m ()
withXML f = do
xml <- awaitXML
maybe (return ()) f xml
maybeXML
:: Monad m => NestingXML o m a -> (Event -> NestingXML o m a) -> NestingXML o m a
maybeXML whenNothing withJust = do
xml <- awaitXML
maybe whenNothing withJust xml
awaitCloser :: Monad m => Int -> NestingXML o m ()
awaitCloser lvl = do
fix $ \loop -> do
lvl' <- nesting
when (lvl' >= lvl) $ do
withXML $ \xml -> do
loop
nextElement :: Monad m => NestingXML o m (Maybe Event)
nextElement = do
lvl <- nesting
fix $ \loop -> do
xml <- awaitXML
case xml of
Nothing -> return Nothing
Just (EventBeginElement _ _) -> do
return xml
Just _ -> do
lvl' <- nesting
if (lvl'>=lvl) then loop
else return Nothing
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