Lua filters: use script to initialize the interpreter

The file `init.lua` is used to initialize the Lua interpreter which is
used in Lua filters. This gives users the option to require libraries
which they want to use in all of their filters, and to extend default
modules.

2 files changed, 9 insertions, 13 deletions

diff --git a/src/Text/Pandoc/Lua.hs b/src/Text/Pandoc/Lua.hs
index 1ca67dced..7132ad718 100644
--- a/src/Text/Pandoc/Lua.hs
+++ b/src/Text/Pandoc/Lua.hs
@@ -48,10 +48,11 @@ import Foreign.Lua (FromLuaStack (peek), Lua, LuaException (..),
                     Status (OK), ToLuaStack (push))
 import Text.Pandoc.Class (PandocIO, getCommonState, getMediaBag, setMediaBag)
 import Text.Pandoc.Definition
+import Text.Pandoc.Lua.Filter (LuaFilter, walkMWithLuaFilter)
 import Text.Pandoc.Lua.Packages (LuaPackageParams (..),
                                  installPandocPackageSearcher)
-import Text.Pandoc.Lua.PandocModule (pushMediaBagModule, pushPandocModule)
-import Text.Pandoc.Lua.Filter (LuaFilter, walkMWithLuaFilter)
+import Text.Pandoc.Lua.PandocModule (pushPandocModule) -- TODO: remove
+import Text.Pandoc.Lua.Util (loadScriptFromDataDir)
 import qualified Foreign.Lua as Lua
 import qualified Foreign.Lua.Module.Text as Lua
 
@@ -101,17 +102,11 @@ luaPackageParams datadir = do
 
 -- Initialize the lua state with all required values
 initLuaState :: LuaPackageParams -> Lua ()
-initLuaState luaPkgParams@(LuaPackageParams commonState datadir mbRef) = do
+initLuaState luaPkgParams = do
   Lua.openlibs
   Lua.preloadTextModule "text"
   installPandocPackageSearcher luaPkgParams
-  pushPandocModule datadir
-  -- add MediaBag module
-  push "mediabag"
-  pushMediaBagModule commonState mbRef
-  Lua.rawset (-3)
-  Lua.setglobal "pandoc"
-  return ()
+  loadScriptFromDataDir (luaPkgDataDir luaPkgParams) "init.lua"
 
 pushGlobalFilter :: Lua ()
 pushGlobalFilter = do
diff --git a/src/Text/Pandoc/Lua/PandocModule.hs b/src/Text/Pandoc/Lua/PandocModule.hs
index 744edfe82..75f884c46 100644
--- a/src/Text/Pandoc/Lua/PandocModule.hs
+++ b/src/Text/Pandoc/Lua/PandocModule.hs
@@ -60,7 +60,7 @@ import qualified Text.Pandoc.MediaBag as MB
 
 -- | Push the "pandoc" on the lua stack. Requires the `list` module to be
 -- loaded.
-pushPandocModule :: Maybe FilePath -> Lua ()
+pushPandocModule :: Maybe FilePath -> Lua NumResults
 pushPandocModule datadir = do
   loadScriptFromDataDir datadir "pandoc.lua"
   addFunction "_pipe" pipeFn
@@ -68,6 +68,7 @@ pushPandocModule datadir = do
   addFunction "sha1" sha1HashFn
   addFunction "walk_block" walkBlock
   addFunction "walk_inline" walkInline
+  return 1
 
 walkElement :: (ToLuaStack a, Walkable [Inline] a, Walkable [Block] a)
             => a -> LuaFilter -> Lua NumResults
@@ -99,14 +100,14 @@ readDoc formatSpec content = do
 --
 -- MediaBag submodule
 --
-pushMediaBagModule :: CommonState -> IORef MB.MediaBag -> Lua ()
+pushMediaBagModule :: CommonState -> IORef MB.MediaBag -> Lua NumResults
 pushMediaBagModule commonState mediaBagRef = do
   Lua.newtable
   addFunction "insert" (insertMediaFn mediaBagRef)
   addFunction "lookup" (lookupMediaFn mediaBagRef)
   addFunction "list" (mediaDirectoryFn mediaBagRef)
   addFunction "fetch" (fetch commonState mediaBagRef)
-  return ()
+  return 1
 
 addFunction :: ToHaskellFunction a => String -> a -> Lua ()
 addFunction name fn = do