hw-xml-0.0.0.1: src/HaskellWorks/Data/Xml/Succinct/Cursor/Token.hs

module HaskellWorks.Data.Xml.Succinct.Cursor.Token
  ( xmlTokenAt
  ) where

import qualified Data.Attoparsec.ByteString.Char8               as ABC
import           Data.ByteString.Internal                       as BSI
import           HaskellWorks.Data.Bits.BitWise
import           HaskellWorks.Data.Drop
import           HaskellWorks.Data.Positioning
import           HaskellWorks.Data.RankSelect.Base.Rank1
import           HaskellWorks.Data.RankSelect.Base.Select1
import           HaskellWorks.Data.Xml.Succinct.Cursor.Internal
import           HaskellWorks.Data.Xml.Token.Tokenize
import           Prelude hiding (drop)

xmlTokenAt :: (Rank1 w, Select1 v, TestBit w) => XmlCursor ByteString v w -> Maybe (XmlToken String Double)
xmlTokenAt k = if balancedParens k .?. lastPositionOf (cursorRank k)
  then case ABC.parse parseXmlToken (drop (toCount (xmlCursorPos k)) (cursorText k)) of
    ABC.Fail    {}  -> error "Failed to parse token in cursor"
    ABC.Partial _   -> error "Failed to parse token in cursor"
    ABC.Done    _ r -> Just r
  else Nothing