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{-# LANGUAGE LambdaCase #-}
module Text.Pandoc.Extended
    ( module Text.Pandoc

    , plainToPara
    , newlineToSpace

    , readPlainText
    ) where


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import           Data.Char          (isSpace)
import           Data.Data.Extended (grecT)
import qualified Data.Text          as T
import           Prelude
import           Text.Pandoc


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plainToPara :: [Block] -> [Block]
plainToPara = map $ \case
    Plain inlines -> Para inlines
    block         -> block


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newlineToSpace :: [Inline] -> [Inline]
newlineToSpace = grecT $ \case
    SoftBreak -> Space
    LineBreak -> Space
    inline    -> inline


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-- | A plain-text reader.  Always returns empty metadata.
readPlainText :: T.Text -> Pandoc
readPlainText = Pandoc mempty . pure . Plain . go
  where
    go txt0 = case T.uncons txt0 of
        Nothing           -> []
        Just (' ',  txt1) -> Space : go txt1
        Just ('\r', txt1) -> go txt1
        Just ('\n', txt1) -> SoftBreak : go txt1
        Just (c,    txt1) ->
            let (pre, post) = T.break isSpace txt1 in
            Str (T.cons c pre) : go post