{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE OverloadedStrings #-}
module Text.Pandoc.Filter
( Filter (..)
, applyFilters
) where
import Prelude
import Data.Aeson.TH (deriveJSON, defaultOptions)
import GHC.Generics (Generic)
import Text.Pandoc.Class (PandocIO)
import Text.Pandoc.Definition (Pandoc)
import Text.Pandoc.Options (ReaderOptions)
import qualified Text.Pandoc.Filter.JSON as JSONFilter
import qualified Text.Pandoc.Filter.Lua as LuaFilter
import qualified Text.Pandoc.Filter.Path as Path
import Data.YAML
import qualified Data.Text as T
import System.FilePath (takeExtension)
import Control.Applicative ((<|>))
import Control.Monad (foldM)
data Filter = LuaFilter FilePath
| JSONFilter FilePath
deriving (Show, Generic)
instance FromYAML Filter where
parseYAML node =
(withMap "Filter" $ \m -> do
ty <- m .: "type"
fp <- m .: "path"
case ty of
"lua" -> return $ LuaFilter $ T.unpack fp
"json" -> return $ JSONFilter $ T.unpack fp
_ -> fail $ "Unknown filter type " ++ show (ty :: T.Text)) node
<|>
(withStr "Filter" $ \t -> do
let fp = T.unpack t
case takeExtension fp of
".lua" -> return $ LuaFilter fp
_ -> return $ JSONFilter fp) node
applyFilters :: ReaderOptions
-> [Filter]
-> [String]
-> Pandoc
-> PandocIO Pandoc
applyFilters ropts filters args d = do
expandedFilters <- mapM expandFilterPath filters
foldM applyFilter d expandedFilters
where
applyFilter doc (JSONFilter f) = JSONFilter.apply ropts args f doc
applyFilter doc (LuaFilter f) = LuaFilter.apply ropts args f doc
expandFilterPath :: Filter -> PandocIO Filter
expandFilterPath (LuaFilter fp) = LuaFilter <$> Path.expandFilterPath fp
expandFilterPath (JSONFilter fp) = JSONFilter <$> Path.expandFilterPath fp
$(deriveJSON defaultOptions ''Filter)