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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 ( (>=>), 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
when (not 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)
|
