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{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Lua.Module.Pandoc
Copyright : Copyright © 2017-2020 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.Module.Pandoc
( pushModule
) where
import Control.Monad (when)
import Control.Monad.Except (throwError)
import Data.Default (Default (..))
import Data.Maybe (fromMaybe)
import Foreign.Lua (Lua, NumResults, Optional, Peekable, Pushable)
import System.Exit (ExitCode (..))
import Text.Pandoc.Class.PandocIO (runIO)
import Text.Pandoc.Definition (Block, Inline)
import Text.Pandoc.Lua.Filter (walkInlines, walkBlocks, LuaFilter, SingletonsList (..))
import Text.Pandoc.Lua.Marshaling ()
import Text.Pandoc.Lua.PandocLua (PandocLua, addFunction, liftPandocLua,
loadScriptFromDataDir)
import Text.Pandoc.Walk (Walkable)
import Text.Pandoc.Options (ReaderOptions (readerExtensions))
import Text.Pandoc.Process (pipeProcess)
import Text.Pandoc.Readers (Reader (..), getReader)
import qualified Data.ByteString.Lazy as BL
import qualified Data.ByteString.Lazy.Char8 as BSL
import qualified Data.Text as T
import qualified Foreign.Lua as Lua
import qualified Text.Pandoc.Lua.Util as LuaUtil
import Text.Pandoc.Error
-- | Push the "pandoc" on the lua stack. Requires the `list` module to be
-- loaded.
pushModule :: PandocLua NumResults
pushModule = do
loadScriptFromDataDir "pandoc.lua"
addFunction "read" readDoc
addFunction "pipe" pipeFn
addFunction "walk_block" walkBlock
addFunction "walk_inline" walkInline
return 1
walkElement :: (Walkable (SingletonsList Inline) a,
Walkable (SingletonsList Block) a)
=> a -> LuaFilter -> PandocLua a
walkElement x f = liftPandocLua $ walkInlines f x >>= walkBlocks f
walkInline :: Inline -> LuaFilter -> PandocLua Inline
walkInline = walkElement
walkBlock :: Block -> LuaFilter -> PandocLua Block
walkBlock = walkElement
readDoc :: T.Text -> Optional T.Text -> PandocLua NumResults
readDoc content formatSpecOrNil = liftPandocLua $ do
let formatSpec = fromMaybe "markdown" (Lua.fromOptional formatSpecOrNil)
res <- Lua.liftIO . runIO $
getReader formatSpec >>= \(rdr,es) ->
case rdr of
TextReader r ->
r def{ readerExtensions = es } content
_ -> throwError $ PandocSomeError
"Only textual formats are supported"
case res of
Right pd -> (1 :: NumResults) <$ Lua.push pd -- success, push Pandoc
Left (PandocUnknownReaderError f) -> Lua.raiseError $
"Unknown reader: " <> f
Left (PandocUnsupportedExtensionError e f) -> Lua.raiseError $
"Extension " <> e <> " not supported for " <> f
Left e -> Lua.raiseError $ show e
-- | Pipes input through a command.
pipeFn :: String
-> [String]
-> BL.ByteString
-> PandocLua NumResults
pipeFn command args input = liftPandocLua $ do
(ec, output) <- Lua.liftIO $ pipeProcess Nothing command args input
case ec of
ExitSuccess -> 1 <$ Lua.push output
ExitFailure n -> Lua.raiseError (PipeError (T.pack command) n output)
data PipeError = PipeError
{ pipeErrorCommand :: T.Text
, pipeErrorCode :: Int
, pipeErrorOutput :: BL.ByteString
}
instance Peekable PipeError where
peek idx =
PipeError
<$> (Lua.getfield idx "command" *> Lua.peek (-1) <* Lua.pop 1)
<*> (Lua.getfield idx "error_code" *> Lua.peek (-1) <* Lua.pop 1)
<*> (Lua.getfield idx "output" *> Lua.peek (-1) <* Lua.pop 1)
instance Pushable PipeError where
push pipeErr = do
Lua.newtable
LuaUtil.addField "command" (pipeErrorCommand pipeErr)
LuaUtil.addField "error_code" (pipeErrorCode pipeErr)
LuaUtil.addField "output" (pipeErrorOutput pipeErr)
pushPipeErrorMetaTable
Lua.setmetatable (-2)
where
pushPipeErrorMetaTable :: Lua ()
pushPipeErrorMetaTable = do
v <- Lua.newmetatable "pandoc pipe error"
when v $ LuaUtil.addFunction "__tostring" pipeErrorMessage
pipeErrorMessage :: PipeError -> Lua BL.ByteString
pipeErrorMessage (PipeError cmd errorCode output) = return $ mconcat
[ BSL.pack "Error running "
, BSL.pack $ T.unpack cmd
, BSL.pack " (error code "
, BSL.pack $ show errorCode
, BSL.pack "): "
, if output == mempty then BSL.pack "<no output>" else output
]
|
