diff options
| -rw-r--r-- | doc/lua-filters.md | 27 | ||||
| -rw-r--r-- | src/Text/Pandoc/Lua/Init.hs | 32 |
2 files changed, 31 insertions, 28 deletions
diff --git a/doc/lua-filters.md b/doc/lua-filters.md index ba5f58120..38790ca5d 100644 --- a/doc/lua-filters.md +++ b/doc/lua-filters.md @@ -245,15 +245,28 @@ variables. variable is of type [CommonState] and is read-only. -## Global modules - -There are two modules which are preloaded and accessible through -global variables. The first is `pandoc`, which is described in the -next section. The other is `lpeg`, a package based on Parsing -Expression Grammars (PEG). See the official [LPeg homepage] for -details. +`pandoc` +: The *pandoc* module, described in the next section, is + available through the global `pandoc`. The other modules + described herein are loaded as subfields under their + respective name. + +`lpeg` +: This variable holds the `lpeg` module, a package based on + Parsing Expression Grammars (PEG). It provides excellent + parsing utilities and is documented on the official [LPeg + homepage]. Pandoc will try to load the module through the + normal package mechanism, and fall back to a built-in version + if necessary. + +`re` +: Contains the LPeg.re module, which is built on top of LPeg and + offers an implementation of a [regex engine]. Pandoc will try + to load the module through the normal package mechanism, and + fall back to a built-in version if necessary. [LPeg homepage]: http://www.inf.puc-rio.br/~roberto/lpeg/ +[regex engine]: http://www.inf.puc-rio.br/~roberto/lpeg/re.html # Pandoc Module diff --git a/src/Text/Pandoc/Lua/Init.hs b/src/Text/Pandoc/Lua/Init.hs index 727c79d84..23c51969c 100644 --- a/src/Text/Pandoc/Lua/Init.hs +++ b/src/Text/Pandoc/Lua/Init.hs @@ -1,4 +1,3 @@ -{-# LANGUAGE LambdaCase #-} {-# LANGUAGE OverloadedStrings #-} {- | Module : Text.Pandoc.Lua @@ -14,7 +13,7 @@ module Text.Pandoc.Lua.Init ( runLua ) where -import Control.Monad (when) +import Control.Monad (forM_, when) import Control.Monad.Catch (throwM, try) import Control.Monad.Trans (MonadIO (..)) import Data.Data (Data, dataTypeConstrs, dataTypeOf, showConstr) @@ -46,8 +45,8 @@ initLuaState :: PandocLua () initLuaState = do liftPandocLua Lua.openlibs installPandocPackageSearcher - installLpegSearcher initPandocModule + installLpegSearcher requireGlobalModules loadInitScript "init.lua" where @@ -78,27 +77,18 @@ initLuaState = do _ -> T.pack $ show err requireGlobalModules :: PandocLua () - requireGlobalModules = liftPandocLua $ do - Lua.pushcfunction LPeg.luaopen_lpeg_ptr - Lua.pcall 0 1 Nothing >>= \case - Lua.OK -> do - -- Success. Register as a loaded module. - -- Get table "_LOADED" from registry, add entry. - _ <- Lua.getfield Lua.registryindex Lua.loaded - Lua.pushvalue (Lua.nth 2) - Lua.setfield (Lua.nth 2) "lpeg" - Lua.pop 1 -- pop _LOADED - - _ -> do - -- Maybe LPeg was not compiled into the program. Try loading via - -- the normal package loading mechanism. - pop 1 -- ignore error message + requireGlobalModules = liftPandocLua $ + forM_ ["lpeg", "re"] $ \pkgname -> do + -- Try loading via the normal package loading mechanism, which + -- includes the custom LPeg searcher as a last resort. This + -- means the system installation of the package, should it be + -- available, is preferred. Lua.getglobal "require" - Lua.pushName "lpeg" + Lua.pushName pkgname Lua.call 1 1 -- throws an exception if the module is not found - -- Module on top of stack. Register as global - Lua.setglobal "lpeg" + -- Module on top of stack. Register as global + Lua.setglobal pkgname installLpegSearcher :: PandocLua () installLpegSearcher = liftPandocLua $ do |