pandoc-cli: support -E flag in pandoc-lua

MANUAL.txt

@@ -7102,8 +7102,7 @@ Calling the pandoc executable under the name `pandoc-lua` or with
 `lua` as the first argument will make it function as a standalone
 Lua interpreter. The behavior is mostly identical to that of the
 [standalone `lua` executable][lua standalone], version 5.4.
-However, there is no REPL yet, and the options `-W`, `-E`, and
-`-i` currently don't have any effect.
+However, there is no REPL yet, and the `-i` option has no effect.
 
 [lua standalone]: https://www.lua.org/manual/5.4/manual.html#7
 

pandoc-cli/src/pandoc.hs

@@ -14,13 +14,13 @@ writers.
 module Main where
 import Control.Monad ((<=<))
 import qualified Control.Exception as E
-import HsLua.CLI (Settings (..), runStandalone)
+import HsLua.CLI (EnvBehavior (..), Settings (..), runStandalone)
 import System.Environment (getArgs, getProgName)
 import Text.Pandoc.App ( convertWithOpts, defaultOpts, options
                        , parseOptionsFromArgs)
 import Text.Pandoc.Class (runIOorExplode)
 import Text.Pandoc.Error (handleError)
-import Text.Pandoc.Lua (runLua)
+import Text.Pandoc.Lua (runLua, runLuaNoEnv)
 import Text.Pandoc.Shared (pandocVersion)
 import qualified Text.Pandoc.UTF8 as UTF8
 import PandocCLI.Server
@@ -50,4 +50,8 @@ runLuaInterpreter progName args = do
         }
   runStandalone settings progName args
   where
-    runner _envBehavior = handleError <=< runIOorExplode . runLua
+    runner envBehavior =
+      let runLua' = case envBehavior of
+                      IgnoreEnvVars  -> runLuaNoEnv
+                      ConsultEnvVars -> runLua
+      in handleError <=< runIOorExplode . runLua'

src/Text/Pandoc/Lua.hs

@@ -20,11 +20,12 @@ module Text.Pandoc.Lua
   , Global(..)
   , setGlobals
   , runLua
+  , runLuaNoEnv
   ) where
 
 import Text.Pandoc.Lua.Filter (applyFilter)
 import Text.Pandoc.Lua.Global (Global (..), setGlobals)
-import Text.Pandoc.Lua.Init (runLua)
+import Text.Pandoc.Lua.Init (runLua, runLuaNoEnv)
 import Text.Pandoc.Lua.Reader (readCustom)
 import Text.Pandoc.Lua.Writer (writeCustom)
 import Text.Pandoc.Lua.Orphans ()

src/Text/Pandoc/Lua/Init.hs

@@ -12,6 +12,7 @@ Functions to initialize the Lua interpreter.
 -}
 module Text.Pandoc.Lua.Init
   ( runLua
+  , runLuaNoEnv
   ) where
 
 import Control.Monad (forM, forM_, when)
@@ -46,6 +47,19 @@ runLua action =
     initLuaState
     liftPandocLua action
 
+-- | Like 'runLua', but ignores all environment variables like @LUA_PATH@.
+runLuaNoEnv :: (PandocMonad m, MonadIO m)
+            => LuaE PandocError a -> m (Either PandocError a)
+runLuaNoEnv action =
+  runPandocLua . try $ do
+    liftPandocLua $ do
+      -- This is undocumented, but works -- the code is adapted from the
+      -- `lua.c` sources for the default interpreter.
+      Lua.pushboolean True
+      Lua.setfield Lua.registryindex "LUA_NOENV"
+    initLuaState
+    liftPandocLua action
+
 -- | Modules that are loaded at startup and assigned to fields in the
 -- pandoc module.
 --