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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 #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
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.HashMap.Lazy ( HashMap )
import Data.Text ( Text, pack, unpack )
import Data.Text.Encoding ( decodeUtf8 )
import Scripting.Lua ( LuaState, StackValue(..) )
import Scripting.Lua.Aeson ( newstate )
import Text.Pandoc.Definition ( Block(..), Inline(..), Pandoc(..) )
import Text.Pandoc.Lua.PandocModule ( pushPandocModule )
import Text.Pandoc.Lua.StackInstances ()
import Text.Pandoc.Walk
import qualified Data.HashMap.Lazy as HashMap
import qualified Scripting.Lua as Lua
runLuaFilter :: (MonadIO m)
=> FilePath -> [String] -> Pandoc -> m Pandoc
runLuaFilter filterPath args pd = liftIO $ do
lua <- newstate
Lua.openlibs lua
-- create table in registry to store filter functions
Lua.push lua ("PANDOC_FILTER_FUNCTIONS"::String)
Lua.newtable lua
Lua.rawset lua Lua.registryindex
-- store module in global "pandoc"
pushPandocModule lua
Lua.setglobal lua "pandoc"
status <- Lua.loadfile lua filterPath
if (status /= 0)
then do
luaErrMsg <- unpack . decodeUtf8 <$> Lua.tostring lua 1
error luaErrMsg
else do
Lua.call lua 0 1
Just luaFilters <- Lua.peek lua (-1)
Lua.push lua (map pack args)
Lua.setglobal lua "PandocParameters"
doc <- runAll luaFilters >=> luaFilter lua "filter_doc" $ pd
Lua.close lua
return doc
runAll :: [LuaFilter] -> Pandoc -> IO Pandoc
runAll [] = return
runAll (x:xs) = walkMWithLuaFilter x >=> runAll xs
luaFilter :: Lua.LuaState -> String -> Pandoc -> IO Pandoc
luaFilter lua luaFn x = do
fnExists <- isLuaFunction lua luaFn
if fnExists
then walkM (Lua.callfunc lua luaFn :: Pandoc -> IO Pandoc) x
else return x
walkMWithLuaFilter :: LuaFilter -> Pandoc -> IO Pandoc
walkMWithLuaFilter (LuaFilter lua inlineFnMap blockFnMap docFnMap) =
walkM (execInlineLuaFilter lua inlineFnMap) >=>
walkM (execBlockLuaFilter lua blockFnMap) >=>
walkM (execDocLuaFilter lua docFnMap)
type InlineFunctionMap = HashMap Text (LuaFilterFunction Inline)
type BlockFunctionMap = HashMap Text (LuaFilterFunction Block)
type DocFunctionMap = HashMap Text (LuaFilterFunction Pandoc)
data LuaFilter =
LuaFilter LuaState InlineFunctionMap BlockFunctionMap DocFunctionMap
newtype LuaFilterFunction a = LuaFilterFunction { functionIndex :: Int }
execDocLuaFilter :: LuaState
-> HashMap Text (LuaFilterFunction Pandoc)
-> Pandoc -> IO Pandoc
execDocLuaFilter lua fnMap x = do
let docFnName = "Doc"
case HashMap.lookup docFnName fnMap of
Nothing -> return x
Just fn -> runLuaFilterFunction lua fn x
execBlockLuaFilter :: LuaState
-> HashMap Text (LuaFilterFunction Block)
-> Block -> IO Block
execBlockLuaFilter lua fnMap x = do
let filterOrId constr = case HashMap.lookup constr fnMap of
Nothing -> return x
Just fn -> runLuaFilterFunction lua fn x
case x of
Plain _ -> filterOrId "Plain"
Para _ -> filterOrId "Para"
LineBlock _ -> filterOrId "LineBlock"
CodeBlock _ _ -> filterOrId "CodeBlock"
RawBlock _ _ -> filterOrId "RawBlock"
BlockQuote _ -> filterOrId "BlockQuote"
OrderedList _ _ -> filterOrId "OrderedList"
BulletList _ -> filterOrId "BulletList"
DefinitionList _ -> filterOrId "DefinitionList"
Header _ _ _ -> filterOrId "Header"
HorizontalRule -> filterOrId "HorizontalRule"
Table _ _ _ _ _ -> filterOrId "Table"
Div _ _ -> filterOrId "Div"
Null -> filterOrId "Null"
execInlineLuaFilter :: LuaState
-> HashMap Text (LuaFilterFunction Inline)
-> Inline -> IO Inline
execInlineLuaFilter lua fnMap x = do
let runFn :: PushViaFilterFunction Inline a => LuaFilterFunction Inline -> a
runFn fn = runLuaFilterFunction lua fn
let tryFilter :: Text -> (LuaFilterFunction Inline -> IO Inline) -> IO Inline
tryFilter fnName callFilterFn =
case HashMap.lookup fnName fnMap of
Nothing -> return x
Just fn -> callFilterFn fn
case x of
LineBreak -> tryFilter "LineBreak" runFn
SoftBreak -> tryFilter "SoftBreak" runFn
Space -> tryFilter "Space" runFn
Cite cs lst -> tryFilter "Cite" $ \fn -> runFn fn lst cs
Code attr str -> tryFilter "Code" $ \fn -> runFn fn str attr
Emph lst -> tryFilter "Emph" $ \fn -> runFn fn lst
Math mt lst -> tryFilter "Math" $ \fn -> runFn fn lst mt
Note blks -> tryFilter "Note" $ \fn -> runFn fn blks
Quoted qt lst -> tryFilter "Quoted" $ \fn -> runFn fn qt lst
RawInline f str -> tryFilter "RawInline" $ \fn -> runFn fn f str
SmallCaps lst -> tryFilter "SmallCaps" $ \fn -> runFn fn lst
Span attr lst -> tryFilter "Span" $ \fn -> runFn fn lst attr
Str str -> tryFilter "Str" $ \fn -> runFn fn str
Strikeout lst -> tryFilter "Strikeout" $ \fn -> runFn fn lst
Strong lst -> tryFilter "Strong" $ \fn -> runFn fn lst
Subscript lst -> tryFilter "Subscript" $ \fn -> runFn fn lst
Superscript lst -> tryFilter "Superscript" $ \fn -> runFn fn lst
Link attr txt (src, tit) -> tryFilter "Link" $
\fn -> runFn fn txt src tit attr
Image attr alt (src, tit) -> tryFilter "Image" $
\fn -> runFn fn alt src tit attr
instance StackValue LuaFilter where
valuetype _ = Lua.TTABLE
push = undefined
peek lua i = do
-- TODO: find a more efficient way of doing this in a typesafe manner.
inlineFnMap <- Lua.peek lua i
blockFnMap <- Lua.peek lua i
docFnMap <- Lua.peek lua i
return $ LuaFilter lua <$> inlineFnMap <*> blockFnMap <*> docFnMap
-- | Helper class for pushing a single value to the stack via a lua function.
-- See @pushViaCall@.
class PushViaFilterFunction a b where
pushViaFilterFunction' :: LuaState -> LuaFilterFunction a -> IO () -> Int -> b
instance (StackValue a) => PushViaFilterFunction a (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 (PushViaFilterFunction a c, StackValue b) =>
PushViaFilterFunction a (b -> c) 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 :: (StackValue a, PushViaFilterFunction a b)
=> LuaState -> LuaFilterFunction a -> b
runLuaFilterFunction lua lf = pushViaFilterFunction' lua lf (return ()) 0
-- | Push the filter function to the top of the stack.
pushFilterFunction :: Lua.LuaState -> LuaFilterFunction a -> 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 a) 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)
isLuaFunction :: Lua.LuaState -> String -> IO Bool
isLuaFunction lua fnName = do
Lua.getglobal lua fnName
res <- Lua.isfunction lua (-1)
Lua.pop lua (-1)
return res
|
