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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.System as System
import Text.Pandoc.Lua.Module.Types as Types
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.system" -> pushWrappedHsFun System.pushModule
"pandoc.types" -> pushWrappedHsFun Types.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
|
