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How to make HsLua.error called from lua_sethook work? #125
Description
I want to limit maximum count of executed instructions with lua_sethook. I wrote some very naive wrapper for it and call HsLua.error from callback, but seems that Lua just ignored the error and execution continued. What should I do?
My example code below. Thanks.
{-# LANGUAGE OverloadedStrings #-}
module Main where
import Control.Monad
import Control.Monad.IO.Class
import Data.ByteString (ByteString)
import Data.String
import Foreign.Ptr
import GHC.IO.Unsafe
import qualified HsLua
foreign import ccall "wrapper"
wrap
:: (HsLua.State -> Ptr () -> ())
-> IO (FunPtr (HsLua.State -> Ptr () -> ()))
foreign import ccall "lua.h" lua_sethook
:: HsLua.State -- ^ Lua State
-> FunPtr (HsLua.State -> Ptr () -> ()) -- ^ Hook callback
-> HsLua.Integer -- ^ Mask
-> HsLua.Integer -- ^ Limit
-> IO HsLua.Integer
everyNthInstruction
:: HsLua.Integer
-> HsLua.LuaE e ()
-> HsLua.LuaE e HsLua.Integer
everyNthInstruction limit m = do st <- HsLua.state
liftIO $ do
cb <- wrap $ \s _ -> unsafePerformIO
$ HsLua.runWith s m
lua_sethook st cb
8 -- LUA_MASKCOUNT
limit
limit :: HsLua.LuaE HsLua.Exception ()
limit = void $ everyNthInstruction 100 $ do liftIO $ putStrLn "Call!"
HsLua.pushString "Limit exceeded"
void HsLua.error
runCode :: ByteString -> IO (Either HsLua.Exception ByteString)
runCode source = HsLua.runEither $ do limit
HsLua.openbase
HsLua.dostring source
HsLua.tostring' (-1)
main :: IO ()
main = runCode (fromString "while(true) do print('a') end") >>= print
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