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{-
Copyright © 2017 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{-# LANGUAGE FlexibleContexts #-}
{- |
Module : Text.Pandoc.Lua.Module.Pandoc
Copyright : Copyright © 2017 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 Data.Default (Default (..))
import Data.Maybe (fromMaybe)
import Data.Text (pack)
import Foreign.Lua (ToLuaStack, FromLuaStack, Lua, NumResults, Optional, liftIO)
import System.Exit (ExitCode (..))
import Text.Pandoc.Class (runIO)
import Text.Pandoc.Definition (Block, Inline)
import Text.Pandoc.Lua.Filter (walkInlines, walkBlocks, LuaFilter)
import Text.Pandoc.Lua.StackInstances ()
import Text.Pandoc.Lua.Util (addFunction, addValue, 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 Foreign.Lua as Lua
-- | Push the "pandoc" on the lua stack. Requires the `list` module to be
-- loaded.
pushModule :: Maybe FilePath -> Lua NumResults
pushModule datadir = do
loadScriptFromDataDir datadir "pandoc.lua"
addFunction "read" readDoc
addFunction "pipe" pipeFn
addFunction "walk_block" walkBlock
addFunction "walk_inline" walkInline
return 1
walkElement :: (ToLuaStack a, Walkable [Inline] a, Walkable [Block] a)
=> a -> LuaFilter -> Lua a
walkElement x f = walkInlines f x >>= walkBlocks f
walkInline :: Inline -> LuaFilter -> Lua Inline
walkInline = walkElement
walkBlock :: Block -> LuaFilter -> Lua Block
walkBlock = walkElement
readDoc :: String -> Optional String -> Lua NumResults
readDoc content formatSpecOrNil = do
let formatSpec = fromMaybe "markdown" (Lua.fromOptional formatSpecOrNil)
case getReader formatSpec of
Left s -> Lua.raiseError s -- Unknown reader
Right (reader, es) ->
case reader of
TextReader r -> do
res <- liftIO $ runIO $ r def{ readerExtensions = es } (pack content)
case res of
Right pd -> (1 :: NumResults) <$ Lua.push pd -- success, push Pandoc
Left s -> Lua.raiseError (show s) -- error while reading
_ -> Lua.raiseError "Only string formats are supported at the moment."
-- | Pipes input through a command.
pipeFn :: String
-> [String]
-> BL.ByteString
-> Lua NumResults
pipeFn command args input = do
(ec, output) <- liftIO $ pipeProcess Nothing command args input
case ec of
ExitSuccess -> 1 <$ Lua.push output
ExitFailure n -> Lua.raiseError (PipeError command n output)
data PipeError = PipeError
{ pipeErrorCommand :: String
, pipeErrorCode :: Int
, pipeErrorOutput :: BL.ByteString
}
instance FromLuaStack 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 ToLuaStack PipeError where
push pipeErr = do
Lua.newtable
addValue "command" (pipeErrorCommand pipeErr)
addValue "error_code" (pipeErrorCode pipeErr)
addValue "output" (pipeErrorOutput pipeErr)
pushPipeErrorMetaTable
Lua.setmetatable (-2)
where
pushPipeErrorMetaTable :: Lua ()
pushPipeErrorMetaTable = do
v <- Lua.newmetatable "pandoc pipe error"
when v $ addFunction "__tostring" pipeErrorMessage
pipeErrorMessage :: PipeError -> Lua BL.ByteString
pipeErrorMessage (PipeError cmd errorCode output) = return $ mconcat
[ BSL.pack "Error running "
, BSL.pack cmd
, BSL.pack " (error code "
, BSL.pack $ show errorCode
, BSL.pack "): "
, if output == mempty then BSL.pack "<no output>" else output
]
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