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|
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE NoImplicitPrelude #-}
{- |
Module : Text.Pandoc.Lua.Module.Pandoc
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.Module.Pandoc
( pushModule
) where
import Prelude
import Control.Monad (when)
import Data.Default (Default (..))
import Data.Maybe (fromMaybe)
import Data.Text (pack)
import Foreign.Lua (Lua, NumResults, Optional, Peekable, Pushable)
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.Marshaling ()
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
import qualified Text.Pandoc.Lua.Util as LuaUtil
-- | Push the "pandoc" on the lua stack. Requires the `list` module to be
-- loaded.
pushModule :: Maybe FilePath -> Lua NumResults
pushModule datadir = do
LuaUtil.loadScriptFromDataDir datadir "pandoc.lua"
LuaUtil.addFunction "read" readDoc
LuaUtil.addFunction "pipe" pipeFn
LuaUtil.addFunction "walk_block" walkBlock
LuaUtil.addFunction "walk_inline" walkInline
return 1
walkElement :: (Pushable 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 <- Lua.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) <- Lua.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 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 cmd
, BSL.pack " (error code "
, BSL.pack $ show errorCode
, BSL.pack "): "
, if output == mempty then BSL.pack "<no output>" else output
]
|
