d126c26 · typeable/pandoc

git.iko.soy/typeable/pandoc

Lua filter internals: push Shared.Element as userdata

Hierarchical Elements were pushed to Lua as plain tables. This is simple, but has the disadvantage that marshaling is eager: all child elements will be marshaled as part of the object. Using a Lua userdata object instead allows lazy access to fields, causing content marshaling just (but also each time) when a field is accessed. Filters which do not traverse the full element contents tree become faster as a result.

commitd126c26dd5f9eaed17462a3f1836b0edaf79e11c authorAlbert Krewinkel <albert@zeitkraut.de> dateSat 13 Oct 2018, 14:57 (8 years ago) parent3db9e15

1 file changed+24−19

compare with master

unifiedsplit

src/Text/Pandoc/Lua/StackInstances.hs+24−19

src/Text/Pandoc/Lua/StackInstances.hs+24−19

@@ -36,9 +36,10 @@ module Text.Pandoc.Lua.StackInstances () where

3636

3737import Prelude

3838import Control.Applicative ((<|>))

39−import Control.Monad (when)

4039import Data.Data (showConstr, toConstr)

4140import Foreign.Lua (Lua, Peekable, Pushable, StackIndex)

41+import Foreign.Lua.Userdata ( ensureUserdataMetatable, pushAnyWithMetatable

42+ , metatableName)

4243import Text.Pandoc.Definition

4344import Text.Pandoc.Extensions (Extensions)

4445import Text.Pandoc.Lua.Util (defineHowTo, pushViaConstructor)

@@ -308,24 +309,28 @@ instance Peekable LuaListAttributes where

308309--

309310instance Pushable Element where

310311 push (Blk blk) = Lua.push blk

311− push (Sec lvl num attr label contents) = do

312− Lua.newtable

313− LuaUtil.addField "level" lvl

314− LuaUtil.addField "numbering" num

315− LuaUtil.addField "attr" (LuaAttr attr)

316− LuaUtil.addField "label" label

317− LuaUtil.addField "contents" contents

318− pushSecMetaTable

319− Lua.setmetatable (-2)

320− where

321− pushSecMetaTable :: Lua ()

322− pushSecMetaTable = do

323− inexistant <- Lua.newmetatable "PandocElementSec"

324− when inexistant $ do

325− LuaUtil.addField "t" "Sec"

326− Lua.push "__index"

327− Lua.pushvalue (-2)

328− Lua.rawset (-3)

312+ push sec = pushAnyWithMetatable pushElementMetatable sec

313+ where

314+ pushElementMetatable = ensureUserdataMetatable (metatableName sec) $

315+ LuaUtil.addFunction "__index" indexElement

316+

317+instance Peekable Element where

318+ peek idx = Lua.ltype idx >>= \case

319+ Lua.TypeUserdata -> Lua.peekAny idx

320+ _ -> Blk <$> Lua.peek idx

321+

322+indexElement :: Element -> String -> Lua Lua.NumResults

323+indexElement = \case

324+ (Blk _) -> const (1 <$ Lua.pushnil) -- this shouldn't happen

325+ (Sec lvl num attr label contents) -> fmap (return 1) . \case

326+ "level" -> Lua.push lvl

327+ "numbering" -> Lua.push num

328+ "attr" -> Lua.push (LuaAttr attr)

329+ "label" -> Lua.push label

330+ "contents" -> Lua.push contents

331+ "tag" -> Lua.push "Sec"

332+ "t" -> Lua.push "Sec"

333+ _ -> Lua.pushnil

329334

330335

331336--