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{-
Copyright (C) 2012 John MacFarlane <jgm@berkeley.edu>
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.Slides
Copyright : Copyright (C) 2012 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Utility functions for splitting documents into slides for slide
show formats (dzslides, s5, slidy, beamer).
-}
module Text.Pandoc.Slides ( toSlideElements, SlideElement(..) ) where
import Text.Pandoc.Definition
import Text.ParserCombinators.Parsec
import Text.Parsec.Pos (initialPos)
import Control.Monad
data SlideElement = SectionSlide Int [Inline]
| ContentSlide [Inline] [Block] -- title - contents
deriving (Read, Show)
toSlideElements :: [Block] -> [SlideElement]
toSlideElements bs =
case parse (pElements $ getSlideLevel bs) "blocks" bs of
Left err -> error $ show err
Right res -> res
satisfies :: (Block -> Bool) -> GenParser Block () Block
satisfies f = token show (const $ initialPos "blocks")
(\x -> if f x then Just x else Nothing)
pElements :: Int -> GenParser Block () [SlideElement]
pElements slideLevel = do
res <- many (pSectionSlide slideLevel <|> pContentSlide slideLevel)
eof
return res
pContentSlide :: Int -> GenParser Block () SlideElement
pContentSlide slideLevel = try $ do
hrs <- many $ satisfies (== HorizontalRule)
Header _ tit <- option (Header 1 []) $ satisfies (isHeader (== slideLevel))
xs <- many $ try $ notFollowedBy (satisfies (== HorizontalRule)) >>
notFollowedBy (satisfies (isHeader (<= slideLevel))) >>
anyToken
guard $ not (null hrs && null tit && null xs) -- make sure we can't match empty
return $ ContentSlide tit xs
pSectionSlide :: Int -> GenParser Block () SlideElement
pSectionSlide slideLevel = try $ do
skipMany $ satisfies (== HorizontalRule)
Header lvl txt <- satisfies (isHeader (< slideLevel))
return $ SectionSlide lvl txt
isHeader :: (Int -> Bool) -> Block -> Bool
isHeader f (Header n _) = f n
isHeader _ _ = False
-- | Find level of header that starts slides (defined as the least header
-- level that occurs before a non-header/non-hrule in the blocks).
getSlideLevel :: [Block] -> Int
getSlideLevel = go 6
where go least (Header n _ : x : xs)
| n < least && nonHOrHR x = go n xs
| otherwise = go least (x:xs)
go least (_ : xs) = go least xs
go least [] = least
nonHOrHR (Header _ _) = False
nonHOrHR (HorizontalRule) = False
nonHOrHR _ = True
|
