support for interpretation of a lua file

LuaIntegration.hs

module LuaIntegration where

import qualified Scripting.Lua as Lua

lua_noerrors = 0
lua_yield	= 1
lua_errrun = 2
lua_errsyntax = 3
lua_errmem = 4

dofile :: Lua.LuaState -> String -> IO Int
dofile s name = do
    res <- Lua.loadfile s name
    if (res == lua_noerrors)
    	then print $ "loaded file correctly:" ++ name
      else reportError $ "error while loading file: " ++ name
    let handlePcall x
          | x == lua_noerrors = print $ "executed file correctly:" ++ name
          | x == lua_errrun = reportError "run-error"
          | x == lua_errsyntax = reportError "syntax-error"
          | x == lua_errmem = reportError "memory-allocation-error"
          | otherwise = reportError ("unknown error(code " ++ show x ++ ") when executing file:" ++ name)
    Lua.pcall s 0 0 0 >>= handlePcall 
    return res
      where reportError desc = do
                                  stackDump s
                                  err <- Lua.tostring s (-1)
                                  Lua.pop s 1 -- remove error message
                                  error $ desc ++ " - " ++ err

stackDump ::  Lua.LuaState -> IO ()
stackDump s = do
      print "stackdump:"
      top <- Lua.gettop s
      doLevel 1 top
        where doLevel n top
                | n == top = print "end"
                | otherwise = do
                    t <- Lua.ltype s n
                    case t of
                      Lua.TSTRING  -> Lua.tostring s n >>= showLevel n
                      Lua.TBOOLEAN -> Lua.toboolean s n >>= showLevel n
                      Lua.TNUMBER  -> Lua.tonumber s n >>= showLevel n
                      _            -> Lua.typename s t >>= showLevel n
              showLevel n xs = do
                let ss = concat $ replicate n "--->"
                print $ ss ++ "level " ++ show n ++ ", " ++ show xs

output ( -threaded)

mkdir -p tmp
ghc -i.. -threaded simplelua.hs -o tmp/testThreadedLua -outputdir tmp
[1 of 2] Compiling LuaIntegration   ( LuaIntegration.hs, tmp/LuaIntegration.o )
[2 of 2] Compiling Main             ( simplelua.hs, tmp/Main.o )
Linking tmp/testThreadedLua ...
/usr/local/lib/hslua-0.3/ghc-7.0.3/libHShslua-0.3.a(loslib.o): In function `os_tmpname':
loslib.c:(.text+0x35): warning: the use of `tmpnam' is dangerous, better use `mkstemp'
./tmp/testThreadedLua
Hello from Lua
"stackdump:"
"end"
testThreadedLua: error while loading file: script_sample.lua - [string "script_sample.lua"]:4: unexpected symbol near '�'

output (no -threaded)

mkdir -p tmp
ghc -i.. simplelua.hs -o tmp/test -outputdir tmp
[1 of 2] Compiling LuaIntegration   ( LuaIntegration.hs, tmp/LuaIntegration.o )
[2 of 2] Compiling Main             ( simplelua.hs, tmp/Main.o )
Linking tmp/test ...
/usr/local/lib/hslua-0.3/ghc-7.0.3/libHShslua-0.3.a(loslib.o): In function `os_tmpname':
loslib.c:(.text+0x35): warning: the use of `tmpnam' is dangerous, better use `mkstemp'
./tmp/test
Hello from Lua
"loaded file correctly:script_sample.lua"
hello from lua-script
"executed file correctly:script_sample.lua"

simplelua.hs

import qualified Scripting.Lua as Lua
import LuaIntegration

main = do
    l <- Lua.newstate
    Lua.openlibs l
    Lua.callproc l "print" "Hello from Lua"
    dofile l "script_sample.lua"
    Lua.close l

sript_sample.lua

print("hello from lua-script")