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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 #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{- |
Module : Text.Pandoc.Lua
Copyright : Copyright © 2017 Albert Krewinkel
License : GNU GPL, version 2 or above
Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
Stability : alpha
Pandoc lua utils.
-}
module Text.Pandoc.Lua ( runLuaFilter, pushPandocModule ) where
import Control.Monad (unless, when, (>=>))
import Control.Monad.Trans (MonadIO (..))
import Data.Map (Map)
import Scripting.Lua (LuaState, StackValue (..))
import Text.Pandoc.Definition
import Text.Pandoc.Lua.PandocModule (pushPandocModule)
import Text.Pandoc.Lua.StackInstances ()
import Text.Pandoc.Walk
import qualified Data.Map as Map
import qualified Scripting.Lua as Lua
runLuaFilter :: (MonadIO m)
=> FilePath -> [String] -> Pandoc -> m Pandoc
runLuaFilter filterPath args pd = liftIO $ do
lua <- Lua.newstate
Lua.openlibs lua
-- create table in registry to store filter functions
Lua.push lua "PANDOC_FILTER_FUNCTIONS"
Lua.newtable lua
Lua.rawset lua Lua.registryindex
-- store module in global "pandoc"
pushPandocModule lua
Lua.setglobal lua "pandoc"
top <- Lua.gettop lua
status <- Lua.loadfile lua filterPath
if (status /= 0)
then do
Just luaErrMsg <- Lua.peek lua 1
error luaErrMsg
else do
Lua.call lua 0 Lua.multret
newtop <- Lua.gettop lua
-- Use the implicitly defined global filter if nothing was returned
when (newtop - top < 1) $ pushGlobalFilter lua
Just luaFilters <- Lua.peek lua (-1)
Lua.push lua args
Lua.setglobal lua "PandocParameters"
doc <- runAll luaFilters pd
Lua.close lua
return doc
pushGlobalFilter :: LuaState -> IO ()
pushGlobalFilter lua =
Lua.newtable lua
*> Lua.getglobal2 lua "pandoc.global_filter"
*> Lua.call lua 0 1
*> Lua.rawseti lua (-2) 1
runAll :: [LuaFilter] -> Pandoc -> IO Pandoc
runAll [] = return
runAll (x:xs) = walkMWithLuaFilter x >=> runAll xs
walkMWithLuaFilter :: LuaFilter -> Pandoc -> IO Pandoc
walkMWithLuaFilter (LuaFilter lua fnMap) =
walkM (execInlineLuaFilter lua fnMap) >=>
walkM (execBlockLuaFilter lua fnMap) >=>
walkM (execMetaLuaFilter lua fnMap) >=>
walkM (execDocLuaFilter lua fnMap)
type FunctionMap = Map String LuaFilterFunction
data LuaFilter = LuaFilter LuaState FunctionMap
newtype LuaFilterFunction = LuaFilterFunction { functionIndex :: Int }
execDocLuaFilter :: LuaState
-> FunctionMap
-> Pandoc -> IO Pandoc
execDocLuaFilter lua fnMap x = do
let docFnName = "Doc"
case Map.lookup docFnName fnMap of
Nothing -> return x
Just fn -> runLuaFilterFunction lua fn x
execMetaLuaFilter :: LuaState
-> FunctionMap
-> Pandoc -> IO Pandoc
execMetaLuaFilter lua fnMap pd@(Pandoc meta blks) = do
let metaFnName = "Meta"
case Map.lookup metaFnName fnMap of
Nothing -> return pd
Just fn -> do
meta' <- runLuaFilterFunction lua fn meta
return $ Pandoc meta' blks
execBlockLuaFilter :: LuaState
-> FunctionMap
-> Block -> IO Block
execBlockLuaFilter lua fnMap x = do
let tryFilter :: String -> IO Block
tryFilter filterFnName =
case Map.lookup filterFnName fnMap of
Nothing -> return x
Just fn -> runLuaFilterFunction lua fn x
case x of
BlockQuote _ -> tryFilter "BlockQuote"
BulletList _ -> tryFilter "BulletList"
CodeBlock _ _ -> tryFilter "CodeBlock"
DefinitionList _ -> tryFilter "DefinitionList"
Div _ _ -> tryFilter "Div"
Header _ _ _ -> tryFilter "Header"
HorizontalRule -> tryFilter "HorizontalRule"
LineBlock _ -> tryFilter "LineBlock"
Null -> tryFilter "Null"
Para _ -> tryFilter "Para"
Plain _ -> tryFilter "Plain"
RawBlock _ _ -> tryFilter "RawBlock"
OrderedList _ _ -> tryFilter "OrderedList"
Table _ _ _ _ _ -> tryFilter "Table"
execInlineLuaFilter :: LuaState
-> FunctionMap
-> Inline -> IO Inline
execInlineLuaFilter lua fnMap x = do
let tryFilter :: String -> IO Inline
tryFilter filterFnName =
case Map.lookup filterFnName fnMap of
Nothing -> return x
Just fn -> runLuaFilterFunction lua fn x
let tryFilterAlternatives :: [String] -> IO Inline
tryFilterAlternatives [] = return x
tryFilterAlternatives (fnName : alternatives) =
case Map.lookup fnName fnMap of
Nothing -> tryFilterAlternatives alternatives
Just fn -> runLuaFilterFunction lua fn x
case x of
Cite _ _ -> tryFilter "Cite"
Code _ _ -> tryFilter "Code"
Emph _ -> tryFilter "Emph"
Image _ _ _ -> tryFilter "Image"
LineBreak -> tryFilter "LineBreak"
Link _ _ _ -> tryFilter "Link"
Math DisplayMath _ -> tryFilterAlternatives ["DisplayMath", "Math"]
Math InlineMath _ -> tryFilterAlternatives ["InlineMath", "Math"]
Note _ -> tryFilter "Note"
Quoted DoubleQuote _ -> tryFilterAlternatives ["DoubleQuoted", "Quoted"]
Quoted SingleQuote _ -> tryFilterAlternatives ["SingleQuoted", "Quoted"]
RawInline _ _ -> tryFilter "RawInline"
SmallCaps _ -> tryFilter "SmallCaps"
SoftBreak -> tryFilter "SoftBreak"
Space -> tryFilter "Space"
Span _ _ -> tryFilter "Span"
Str _ -> tryFilter "Str"
Strikeout _ -> tryFilter "Strikeout"
Strong _ -> tryFilter "Strong"
Subscript _ -> tryFilter "Subscript"
Superscript _ -> tryFilter "Superscript"
instance StackValue LuaFilter where
valuetype _ = Lua.TTABLE
push = undefined
peek lua idx = fmap (LuaFilter lua) <$> Lua.peek lua idx
-- | Helper class for pushing a single value to the stack via a lua function.
-- See @pushViaCall@.
class PushViaFilterFunction a where
pushViaFilterFunction' :: LuaState -> LuaFilterFunction -> IO () -> Int -> a
instance StackValue a => PushViaFilterFunction (IO a) where
pushViaFilterFunction' lua lf pushArgs num = do
pushFilterFunction lua lf
pushArgs
Lua.call lua num 1
mbres <- Lua.peek lua (-1)
case mbres of
Nothing -> error $ "Error while trying to get a filter's return "
++ "value from lua stack."
Just res -> res <$ Lua.pop lua 1
instance (StackValue a, PushViaFilterFunction b) =>
PushViaFilterFunction (a -> b) where
pushViaFilterFunction' lua lf pushArgs num x =
pushViaFilterFunction' lua lf (pushArgs *> push lua x) (num + 1)
-- | Push an value to the stack via a lua filter function. The function is
-- called with all arguments that are passed to this function and is expected to
-- return a single value.
runLuaFilterFunction :: PushViaFilterFunction a
=> LuaState -> LuaFilterFunction -> a
runLuaFilterFunction lua lf = pushViaFilterFunction' lua lf (return ()) 0
-- | Push the filter function to the top of the stack.
pushFilterFunction :: Lua.LuaState -> LuaFilterFunction -> IO ()
pushFilterFunction lua lf = do
-- The function is stored in a lua registry table, retrieve it from there.
push lua ("PANDOC_FILTER_FUNCTIONS"::String)
Lua.rawget lua Lua.registryindex
Lua.rawgeti lua (-1) (functionIndex lf)
Lua.remove lua (-2) -- remove registry table from stack
instance StackValue LuaFilterFunction where
valuetype _ = Lua.TFUNCTION
push lua v = pushFilterFunction lua v
peek lua i = do
isFn <- Lua.isfunction lua i
unless isFn (error $ "Not a function at index " ++ (show i))
Lua.pushvalue lua i
push lua ("PANDOC_FILTER_FUNCTIONS"::String)
Lua.rawget lua Lua.registryindex
len <- Lua.objlen lua (-1)
Lua.insert lua (-2)
Lua.rawseti lua (-2) (len + 1)
Lua.pop lua 1
return . Just $ LuaFilterFunction (len + 1)
|
