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|
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.Readers.Custom
Copyright : Copyright (C) 2021 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Supports custom parsers written in Lua which produce a Pandoc AST.
-}
module Text.Pandoc.Readers.Custom ( readCustom ) where
import Control.Exception
import Control.Monad (when)
import HsLua as Lua hiding (Operation (Div), render)
import Control.Monad.IO.Class (MonadIO)
import Text.Pandoc.Definition
import Text.Pandoc.Class (PandocMonad, report)
import Text.Pandoc.Logging
import Text.Pandoc.Lua (Global (..), runLua, setGlobals)
import Text.Pandoc.Lua.PandocLua
import Text.Pandoc.Lua.Marshal.Pandoc (peekPandoc)
import Text.Pandoc.Lua.Util (dofileWithTraceback, callWithTraceback,
pcallWithTraceback)
import Text.Pandoc.Options
import Text.Pandoc.Sources (ToSources(..), sourcesToText)
import qualified Data.Text as T
-- | Convert custom markup to Pandoc.
readCustom :: (PandocMonad m, MonadIO m, ToSources s)
=> FilePath -> ReaderOptions -> s -> m Pandoc
readCustom luaFile opts srcs = do
let globals = [ PANDOC_SCRIPT_FILE luaFile ]
res <- runLua $ do
setGlobals globals
stat <- dofileWithTraceback luaFile
-- check for error in lua script (later we'll change the return type
-- to handle this more gracefully):
when (stat /= Lua.OK)
Lua.throwErrorAsException
parseCustom
case res of
Left msg -> throw msg
Right doc -> return doc
where
parseCustom = do
let input = toSources srcs
getglobal "Reader"
push input
push opts
pcallWithTraceback 2 1 >>= \case
OK -> forcePeek $ peekPandoc top
ErrRun -> do
-- Caught a runtime error. Check if parsing might work if we
-- pass a string instead of a Sources list, then retry.
runPeek (peekText top) >>= \case
Failure {} ->
-- not a string error object. Bail!
throwErrorAsException
Success errmsg -> do
if "string expected, got pandoc Sources" `T.isInfixOf` errmsg
then do
pop 1
_ <- unPandocLua $ do
report $ Deprecated "old Reader function signature" $
T.unlines
[ "Reader functions should accept a sources list; "
, "functions expecting `string` input are deprecated. "
, "Use `tostring` to convert the first argument to a "
, "string."
]
getglobal "Reader"
push $ sourcesToText input -- push sources as string
push opts
callWithTraceback 2 1
forcePeek $ peekPandoc top
else
-- nothing we can do here
throwErrorAsException
_ -> -- not a runtime error, we won't be able to recover from that
throwErrorAsException
|
