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|
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{- |
Module : Text.Pandoc.Lua.PandocLua
Copyright : Copyright © 2020 Albert Krewinkel
License : GNU GPL, version 2 or above
Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
Stability : alpha
PandocMonad instance which allows execution of Lua operations and which
uses Lua to handle state.
-}
module Text.Pandoc.Lua.PandocLua
( PandocLua (..)
, runPandocLua
, liftPandocLua
, addFunction
, loadScriptFromDataDir
) where
import Control.Monad (when)
import Control.Monad.Catch (MonadCatch, MonadMask, MonadThrow)
import Control.Monad.Except (MonadError (catchError, throwError))
import Control.Monad.IO.Class (MonadIO (liftIO))
import Foreign.Lua (Lua (..), NumResults, Pushable, ToHaskellFunction)
import Text.Pandoc.Class.PandocIO (PandocIO)
import Text.Pandoc.Class.PandocMonad (PandocMonad (..), readDataFile)
import Text.Pandoc.Error (PandocError)
import Text.Pandoc.Lua.Global (Global (..), setGlobals)
import Text.Pandoc.Lua.ErrorConversion (errorConversion)
import qualified Control.Monad.Catch as Catch
import qualified Foreign.Lua as Lua
import qualified Text.Pandoc.Class.IO as IO
import qualified Text.Pandoc.Lua.Util as LuaUtil
-- | Type providing access to both, pandoc and Lua operations.
newtype PandocLua a = PandocLua { unPandocLua :: Lua a }
deriving
( Applicative
, Functor
, Monad
, MonadCatch
, MonadIO
, MonadMask
, MonadThrow
)
-- | Lift a @'Lua'@ operation into the @'PandocLua'@ type.
liftPandocLua :: Lua a -> PandocLua a
liftPandocLua = PandocLua
-- | Evaluate a @'PandocLua'@ computation, running all contained Lua
-- operations..
runPandocLua :: PandocLua a -> PandocIO a
runPandocLua pLua = do
origState <- getCommonState
globals <- defaultGlobals
(result, newState) <- liftIO . Lua.run' errorConversion . unPandocLua $ do
putCommonState origState
liftPandocLua $ setGlobals globals
r <- pLua
c <- getCommonState
return (r, c)
putCommonState newState
return result
instance {-# OVERLAPPING #-} ToHaskellFunction (PandocLua NumResults) where
toHsFun _narg = unPandocLua
instance Pushable a => ToHaskellFunction (PandocLua a) where
toHsFun _narg x = 1 <$ (unPandocLua x >>= Lua.push)
-- | Add a function to the table at the top of the stack, using the given name.
addFunction :: ToHaskellFunction a => String -> a -> PandocLua ()
addFunction name fn = liftPandocLua $ do
Lua.push name
Lua.pushHaskellFunction fn
Lua.rawset (-3)
-- | Load a file from pandoc's data directory.
loadScriptFromDataDir :: FilePath -> PandocLua ()
loadScriptFromDataDir scriptFile = do
script <- readDataFile scriptFile
status <- liftPandocLua $ Lua.dostring script
when (status /= Lua.OK) . liftPandocLua $
LuaUtil.throwTopMessageAsError'
(("Couldn't load '" ++ scriptFile ++ "'.\n") ++)
-- | Global variables which should always be set.
defaultGlobals :: PandocIO [Global]
defaultGlobals = do
commonState <- getCommonState
return
[ PANDOC_API_VERSION
, PANDOC_STATE commonState
, PANDOC_VERSION
]
instance MonadError PandocError PandocLua where
catchError = Catch.catch
throwError = Catch.throwM
instance PandocMonad PandocLua where
lookupEnv = IO.lookupEnv
getCurrentTime = IO.getCurrentTime
getCurrentTimeZone = IO.getCurrentTimeZone
newStdGen = IO.newStdGen
newUniqueHash = IO.newUniqueHash
openURL = IO.openURL
readFileLazy = IO.readFileLazy
readFileStrict = IO.readFileStrict
glob = IO.glob
fileExists = IO.fileExists
getDataFileName = IO.getDataFileName
getModificationTime = IO.getModificationTime
getCommonState = PandocLua $ do
Lua.getglobal "PANDOC_STATE"
Lua.peek Lua.stackTop
putCommonState = PandocLua . setGlobals . (:[]) . PANDOC_STATE
logOutput = IO.logOutput
|
