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|
{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Filter
Copyright : Copyright (C) 2006-2019 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley@edu>
Stability : alpha
Portability : portable
Programmatically modifications of pandoc documents.
-}
module Text.Pandoc.Filter
( Filter (..)
, applyFilters
) where
import Prelude
import Data.Aeson.TH (deriveJSON, defaultOptions)
import Data.Foldable (foldrM)
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 ((<|>))
-- | Type of filter and path to filter file.
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
-- | Modify the given document using a filter.
applyFilters :: ReaderOptions
-> [Filter]
-> [String]
-> Pandoc
-> PandocIO Pandoc
applyFilters ropts filters args d = do
expandedFilters <- mapM expandFilterPath filters
foldrM ($) d $ map applyFilter expandedFilters
where
applyFilter (JSONFilter f) = JSONFilter.apply ropts args f
applyFilter (LuaFilter f) = LuaFilter.apply ropts args f
-- | Expand paths of filters, searching the data directory.
expandFilterPath :: Filter -> PandocIO Filter
expandFilterPath (LuaFilter fp) = LuaFilter <$> Path.expandFilterPath fp
expandFilterPath (JSONFilter fp) = JSONFilter <$> Path.expandFilterPath fp
$(deriveJSON defaultOptions ''Filter)
|
