T.P.Scripting: Refactor the scripting engine.

The new type CustomComponents is exported from T.P.Scripting, and the
ScriptEngine fields are changed. Instead of separate fields for custom
readers and writers, we now have a single function that loads any number
of "components" from a script: these may be custom readers, custom
writers, templates for writers, or extension configs. (Note: it's
possible to have a custom reader and a custom writer for a format
together in the same file.)

Pandoc now checks the folder `custom` in the user's data directory for a
matching script if it can't find one in the local directory. Previously,
the `readers` and `writers` data directories were search for custom
readers and writers, respectively. Scripts in those directories must be
moved to the `custom` folder.

Custom readers used to implement a fallback behavior that allowed to
consume just a string value as input to the `Reader` function. This has
been removed, the first argument is now always a list of sources. Use
`tostring` on that argument to get a string.

Closes #8417.

Signed-off-by: Albert Krewinkel <albert@zeitkraut.de>

1 files changed, 0 insertions, 106 deletions

diff --git a/pandoc-lua-engine/src/Text/Pandoc/Lua/Writer.hs b/pandoc-lua-engine/src/Text/Pandoc/Lua/Writer.hs
deleted file mode 100644
index 91573c87b..000000000
--- a/pandoc-lua-engine/src/Text/Pandoc/Lua/Writer.hs
+++ /dev/null
@@ -1,106 +0,0 @@
-{-# LANGUAGE LambdaCase          #-}
-{-# LANGUAGE OverloadedStrings   #-}
-{-# LANGUAGE TupleSections       #-}
-{-# LANGUAGE TypeApplications    #-}
-{- |
-   Module      : Text.Pandoc.Lua.Writer
-   Copyright   : Copyright (C) 2012-2022 John MacFarlane
-   License     : GNU GPL, version 2 or above
-
-   Maintainer  : John MacFarlane <jgm@berkeley.edu>
-   Stability   : alpha
-   Portability : portable
-
-Conversion of Pandoc documents using a custom Lua writer.
--}
-module Text.Pandoc.Lua.Writer
-  ( writeCustom
-  ) where
-
-import Control.Exception
-import Control.Monad ((<=<))
-import Data.Default (def)
-import Data.Maybe (fromMaybe)
-import Data.Text (Text)
-import HsLua
-import HsLua.Core.Run (newGCManagedState, withGCManagedState)
-import Control.Monad.IO.Class (MonadIO)
-import Text.Pandoc.Class (PandocMonad, findFileWithDataFallback)
-import Text.Pandoc.Error (PandocError (..))
-import Text.Pandoc.Format (ExtensionsConfig (..))
-import Text.Pandoc.Lua.Global (Global (..), setGlobals)
-import Text.Pandoc.Lua.Init (runLuaWith)
-import Text.Pandoc.Lua.Marshal.Format (peekExtensionsConfig)
-import Text.Pandoc.Lua.Marshal.WriterOptions (pushWriterOptions)
-import Text.Pandoc.Writers (Writer (..))
-import qualified Text.Pandoc.Lua.Writer.Classic as Classic
-
--- | Convert Pandoc to custom markup.
-writeCustom :: (PandocMonad m, MonadIO m)
-            => FilePath -> m (Writer m, ExtensionsConfig, Maybe Text)
-writeCustom luaFile = do
-  luaState <- liftIO newGCManagedState
-  luaFile' <- fromMaybe luaFile <$> findFileWithDataFallback "writers" luaFile
-  either throw pure <=< runLuaWith luaState $ do
-    setGlobals [ PANDOC_DOCUMENT mempty
-               , PANDOC_SCRIPT_FILE luaFile'
-               , PANDOC_WRITER_OPTIONS def
-               ]
-    dofileTrace luaFile' >>= \case
-      OK -> pure ()
-      _  -> throwErrorAsException
-    -- Most classic writers contain code that throws an error if a global
-    -- is not present. This would break our check for the existence of a
-    -- "Writer" function. We resort to raw access for that reason, but
-    -- could also catch the error instead.
-    let rawgetglobal x = do
-          pushglobaltable
-          pushName x
-          rawget (nth 2) <* remove (nth 2) -- remove global table
-
-    let writerField = "Pandoc Writer function"
-
-    extsConf <- rawgetglobal "Extensions" >>= \case
-      TypeNil   -> ExtensionsConfig mempty mempty <$ pop 1
-      _         -> forcePeek $ peekExtensionsConfig top `lastly` pop 1
-
-    mtemplate <- rawgetglobal "Template" >>= \case
-      TypeNil   -> pure Nothing
-      TypeFunction -> Just <$> do
-        callTrace 0 1
-        forcePeek $ peekText top `lastly` pop 1
-      _ -> Just <$> do
-        forcePeek $ peekText top `lastly` pop 1
-
-    let addProperties = (, extsConf, mtemplate)
-
-    rawgetglobal "Writer" >>= \case
-      TypeNil -> rawgetglobal "ByteStringWriter" >>= \case
-        TypeNil -> do
-          -- Neither `Writer` nor `BinaryWriter` are defined. Try to
-          -- use the file as a classic writer.
-          pop 1  -- remove nil
-          pure $ addProperties . TextWriter $ \opts doc ->
-            liftIO $ withGCManagedState luaState $ do
-              Classic.runCustom @PandocError opts doc
-        _ -> do
-          -- Binary writer. Writer function is on top of the stack.
-          setfield registryindex writerField
-          pure $ addProperties . ByteStringWriter $ \opts doc ->
-            -- Call writer with document and writer options as arguments.
-            liftIO $ withGCManagedState luaState $ do
-              getfield registryindex writerField
-              push doc
-              pushWriterOptions opts
-              callTrace 2 1
-              forcePeek @PandocError $ peekLazyByteString top
-      _ -> do
-        -- New-type text writer. Writer function is on top of the stack.
-        setfield registryindex writerField
-        pure $ addProperties . TextWriter $ \opts doc ->
-          liftIO $ withGCManagedState luaState $ do
-            getfield registryindex writerField
-            push doc
-            pushWriterOptions opts
-            callTrace 2 1
-            forcePeek @PandocError $ peekText top