{-# LANGUAGE LambdaCase #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE RankNTypes #-} {- | Module : Text.Pandoc.Lua Copyright : Copyright © 2017-2023 Albert Krewinkel License : GNU GPL, version 2 or above Maintainer : Albert Krewinkel Stability : alpha Functions to initialize the Lua interpreter. -} module Text.Pandoc.Lua.Init ( runLua , runLuaNoEnv , runLuaWith ) where import Control.Monad (forM, forM_, when) import Control.Monad.Catch (throwM, try) import Control.Monad.Trans (MonadIO (..)) import Data.Maybe (catMaybes) import Data.Version (makeVersion) import HsLua as Lua hiding (status, try) import Text.Pandoc.Class (PandocMonad (..)) import Text.Pandoc.Data (readDataFile) import Text.Pandoc.Error (PandocError (PandocLuaError)) import Text.Pandoc.Lua.Global (Global (..), setGlobals) import Text.Pandoc.Lua.Marshal.List (newListMetatable, pushListModule) import Text.Pandoc.Lua.PandocLua (PandocLua (..), liftPandocLua) import qualified Data.ByteString.Char8 as Char8 import qualified Data.Text as T import qualified Lua.LPeg as LPeg import qualified HsLua.Aeson import qualified HsLua.Module.DocLayout as Module.Layout import qualified HsLua.Module.Path as Module.Path import qualified HsLua.Module.Zip as Module.Zip import qualified Text.Pandoc.Lua.Module.CLI as Pandoc.CLI import qualified Text.Pandoc.Lua.Module.Format as Pandoc.Format import qualified Text.Pandoc.Lua.Module.JSON as Pandoc.JSON import qualified Text.Pandoc.Lua.Module.MediaBag as Pandoc.MediaBag import qualified Text.Pandoc.Lua.Module.Pandoc as Module.Pandoc import qualified Text.Pandoc.Lua.Module.Scaffolding as Pandoc.Scaffolding import qualified Text.Pandoc.Lua.Module.Structure as Pandoc.Structure import qualified Text.Pandoc.Lua.Module.System as Pandoc.System import qualified Text.Pandoc.Lua.Module.Template as Pandoc.Template import qualified Text.Pandoc.Lua.Module.Text as Pandoc.Text import qualified Text.Pandoc.Lua.Module.Types as Pandoc.Types import qualified Text.Pandoc.Lua.Module.Utils as Pandoc.Utils -- | Run the Lua interpreter, using pandoc's default way of environment -- initialization. runLua :: (PandocMonad m, MonadIO m) => LuaE PandocError a -> m (Either PandocError a) runLua action = do runPandocLuaWith Lua.run . try $ do initLuaState liftPandocLua action runLuaWith :: (PandocMonad m, MonadIO m) => GCManagedState -> LuaE PandocError a -> m (Either PandocError a) runLuaWith luaState action = do runPandocLuaWith (withGCManagedState luaState) . try $ do initLuaState liftPandocLua action -- | Like 'runLua', but ignores all environment variables like @LUA_PATH@. runLuaNoEnv :: (PandocMonad m, MonadIO m) => LuaE PandocError a -> m (Either PandocError a) runLuaNoEnv action = do runPandocLuaWith Lua.run . try $ do liftPandocLua $ do -- This is undocumented, but works -- the code is adapted from the -- `lua.c` sources for the default interpreter. Lua.pushboolean True Lua.setfield Lua.registryindex "LUA_NOENV" initLuaState liftPandocLua action -- | Modules that are loaded at startup and assigned to fields in the -- pandoc module. -- -- Note that @pandoc.List@ is not included here for technical reasons; -- it must be handled separately. loadedModules :: [Module PandocError] loadedModules = [ Pandoc.CLI.documentedModule , Pandoc.Format.documentedModule , Pandoc.JSON.documentedModule , Pandoc.MediaBag.documentedModule , Pandoc.Scaffolding.documentedModule , Pandoc.Structure.documentedModule , Pandoc.System.documentedModule , Pandoc.Template.documentedModule , Pandoc.Text.documentedModule , Pandoc.Types.documentedModule , Pandoc.Utils.documentedModule , Module.Layout.documentedModule { moduleName = "pandoc.layout" } `allSince` [2,18] , Module.Path.documentedModule { moduleName = "pandoc.path" } `allSince` [2,12] , Module.Zip.documentedModule { moduleName = "pandoc.zip" } `allSince` [3,0] ] where allSince mdl version = mdl { moduleFunctions = map (`since` makeVersion version) $ moduleFunctions mdl } -- | Initialize the lua state with all required values initLuaState :: PandocLua () initLuaState = do liftPandocLua Lua.openlibs initJsonMetatable initPandocModule installLpegSearcher setGlobalModules loadInitScript "init.lua" where initPandocModule :: PandocLua () initPandocModule = liftPandocLua $ do -- Push module table registerModule Module.Pandoc.documentedModule -- load modules and add them to the `pandoc` module table. forM_ loadedModules $ \mdl -> do registerModule mdl -- pandoc.text must be require-able as 'text' for backwards compat. when (moduleName mdl == "pandoc.text") $ do getfield registryindex loaded pushvalue (nth 2) setfield (nth 2) "text" pop 1 -- _LOADED -- Shorten name, drop everything before the first dot (if any). let fieldname (Name mdlname) = Name . maybe mdlname snd . Char8.uncons . snd $ Char8.break (== '.') mdlname Lua.setfield (nth 2) (fieldname $ moduleName mdl) -- pandoc.List is low-level and must be opened differently. requirehs "pandoc.List" (const pushListModule) setfield (nth 2) "List" -- assign module to global variable Lua.setglobal "pandoc" loadInitScript :: FilePath -> PandocLua () loadInitScript scriptFile = do script <- readDataFile scriptFile status <- liftPandocLua $ Lua.dostring script when (status /= Lua.OK) . liftPandocLua $ do err <- popException let prefix = "Couldn't load '" <> T.pack scriptFile <> "':\n" throwM . PandocLuaError . (prefix <>) $ case err of PandocLuaError msg -> msg _ -> T.pack $ show err setGlobalModules :: PandocLua () setGlobalModules = liftPandocLua $ do let globalModules = [ ("lpeg", LPeg.luaopen_lpeg_ptr) -- must be loaded first , ("re", LPeg.luaopen_re_ptr) -- re depends on lpeg ] loadedBuiltInModules <- fmap catMaybes . forM globalModules $ \(pkgname, luaopen) -> do Lua.pushcfunction luaopen usedBuiltIn <- Lua.pcall 0 1 Nothing >>= \case OK -> do -- all good, loading succeeded -- register as loaded module so later modules can rely on this Lua.getfield Lua.registryindex Lua.loaded Lua.pushvalue (Lua.nth 2) Lua.setfield (Lua.nth 2) pkgname Lua.pop 1 -- pop _LOADED return True _ -> do -- built-in library failed, load system lib Lua.pop 1 -- ignore error message -- Try loading via the normal package loading mechanism. Lua.getglobal "require" Lua.pushName pkgname Lua.call 1 1 -- Throws an exception if loading failed again! return False -- Module on top of stack. Register as global Lua.setglobal pkgname return $ if usedBuiltIn then Just pkgname else Nothing -- Remove module entry from _LOADED table in registry if we used a -- built-in library. This ensures that later calls to @require@ will -- prefer the shared library, if any. forM_ loadedBuiltInModules $ \pkgname -> do Lua.getfield Lua.registryindex Lua.loaded Lua.pushnil Lua.setfield (Lua.nth 2) pkgname Lua.pop 1 -- registry installLpegSearcher :: PandocLua () installLpegSearcher = liftPandocLua $ do Lua.getglobal' "package.searchers" Lua.pushHaskellFunction $ Lua.state >>= liftIO . LPeg.lpeg_searcher Lua.rawseti (Lua.nth 2) . (+1) . fromIntegral =<< Lua.rawlen (Lua.nth 2) Lua.pop 1 -- remove 'package.searchers' from stack -- | Setup the metatable that's assigned to Lua tables that were created -- from/via JSON arrays. initJsonMetatable :: PandocLua () initJsonMetatable = liftPandocLua $ do newListMetatable HsLua.Aeson.jsonarray (pure ()) Lua.pop 1 -- | Evaluate a @'PandocLua'@ computation, running all contained Lua -- operations. runPandocLuaWith :: (PandocMonad m, MonadIO m) => (forall b. LuaE PandocError b -> IO b) -> PandocLua a -> m a runPandocLuaWith runner pLua = do origState <- getCommonState globals <- defaultGlobals (result, newState) <- liftIO . runner . unPandocLua $ do putCommonState origState liftPandocLua $ setGlobals globals r <- pLua c <- getCommonState return (r, c) putCommonState newState return result -- | Global variables which should always be set. defaultGlobals :: PandocMonad m => m [Global] defaultGlobals = do commonState <- getCommonState return [ PANDOC_API_VERSION , PANDOC_STATE commonState , PANDOC_VERSION ]