hledger/tools/pandoc-drop-toc.hs
2017-01-10 08:49:05 -08:00

41 lines
1.1 KiB
Haskell

#!/usr/bin/env stack
{- stack runghc --verbosity info
--package pandoc
-}
-- Remove a table of contents marker
-- (a bullet list item containing "toc[-N[-M]]")
{-# LANGUAGE OverloadedStrings #-}
import Data.Char (isDigit)
import Data.List.Split
import Data.Maybe
import Safe
import Text.Pandoc.JSON
main :: IO ()
main = toJSONFilter dropToc
dropHtmlBlocks :: Block -> Block
dropHtmlBlocks (RawBlock (Format "html") _) = Plain []
dropHtmlBlocks x = x
-- BulletList
-- [ [Plain [Str "toc"]] ]
dropToc :: Block -> Block
dropToc (BulletList is) =
BulletList $ filter (not.null) $ map (filter isNotToc) is
where
isNotToc (Plain [Str s]) | isJust $ tocParams s = False
isNotToc _ = True
dropToc x = x
tocParams :: String -> Maybe (Maybe Int, Maybe Int)
tocParams s =
case splitOn "-" s of
["toc"] -> Just (Nothing, Nothing)
["toc",a] | all isDigit a -> Just (Nothing, readMay a)
["toc",a,b] | all isDigit a, all isDigit b -> Just (readMay a, readMay b)
_ -> Nothing