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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE ScopedTypeVariables #-}
{- |
Module : Text.Pandoc.Lua.Packages
Copyright : Copyright © 2017-2019 Albert Krewinkel
License : GNU GPL, version 2 or above
Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
Stability : alpha
Pandoc module for lua.
-}
module Text.Pandoc.Lua.Packages
( LuaPackageParams (..)
, installPandocPackageSearcher
) where
import Prelude
import Control.Monad (forM_)
import Data.ByteString (ByteString)
import Foreign.Lua (Lua, NumResults, liftIO)
import Text.Pandoc.Class (readDataFile, runIO, setUserDataDir)
import qualified Foreign.Lua as Lua
import Text.Pandoc.Lua.Module.Pandoc as Pandoc
import Text.Pandoc.Lua.Module.MediaBag as MediaBag
import Text.Pandoc.Lua.Module.Utils as Utils
-- | Parameters used to create lua packages/modules.
data LuaPackageParams = LuaPackageParams
{ luaPkgDataDir :: Maybe FilePath
}
-- | Insert pandoc's package loader as the first loader, making it the default.
installPandocPackageSearcher :: LuaPackageParams -> Lua ()
installPandocPackageSearcher luaPkgParams = do
Lua.getglobal' "package.searchers"
shiftArray
Lua.pushHaskellFunction (pandocPackageSearcher luaPkgParams)
Lua.rawseti (Lua.nthFromTop 2) 1
Lua.pop 1 -- remove 'package.searchers' from stack
where
shiftArray = forM_ [4, 3, 2, 1] $ \i -> do
Lua.rawgeti (-1) i
Lua.rawseti (-2) (i + 1)
-- | Load a pandoc module.
pandocPackageSearcher :: LuaPackageParams -> String -> Lua NumResults
pandocPackageSearcher pkgParams pkgName =
case pkgName of
"pandoc" -> let datadir = luaPkgDataDir pkgParams
in pushWrappedHsFun (Pandoc.pushModule datadir)
"pandoc.mediabag" -> pushWrappedHsFun MediaBag.pushModule
"pandoc.utils" -> let datadir = luaPkgDataDir pkgParams
in pushWrappedHsFun (Utils.pushModule datadir)
_ -> searchPureLuaLoader
where
pushWrappedHsFun f = do
Lua.pushHaskellFunction f
return 1
searchPureLuaLoader = do
let filename = pkgName ++ ".lua"
modScript <- liftIO (dataDirScript (luaPkgDataDir pkgParams) filename)
case modScript of
Just script -> pushWrappedHsFun (loadStringAsPackage pkgName script)
Nothing -> do
Lua.push ("\n\tno file '" ++ filename ++ "' in pandoc's datadir")
return 1
loadStringAsPackage :: String -> ByteString -> Lua NumResults
loadStringAsPackage pkgName script = do
status <- Lua.dostring script
if status == Lua.OK
then return (1 :: NumResults)
else do
msg <- Lua.popValue
Lua.raiseError ("Error while loading `" <> pkgName <> "`.\n" <> msg)
-- | Get the ByteString representation of the pandoc module.
dataDirScript :: Maybe FilePath -> FilePath -> IO (Maybe ByteString)
dataDirScript datadir moduleFile = do
res <- runIO $ setUserDataDir datadir >> readDataFile moduleFile
return $ case res of
Left _ -> Nothing
Right s -> Just s
|
