diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,55 @@
 ## Changelog
 
+### 1.1.0
+
+Released 2020-03-25.
+
+**WARNING:** The changes in this release are experimental. It is
+recommended to skip this release unless the newly introduced
+features are required.
+
+- Allow custom error handling: conversion of Lua errors to
+  Haskell exceptions and back is made configurable. Users can
+  define their own exception/error handling strategies, even
+  opening up the option to pass arbitrary exceptions through Lua.
+
+    - New types exported from `Foreign.Lua.Types`:
+
+        - `ErrorConversion`: defines the ways in which exceptions
+          and errors are handled and converted.
+        - `LuaEnvironment`: environment in which Lua computations
+          are evaluated. Contains the Lua interpreter state and
+          the error conversion strategy.
+
+    - The environment of the `Lua` type is changed from a plain
+      Lua `State` to the above mentioned `LuaEnvironment`.
+
+    - New functions `run'` is exported from `Foreign.Lua.Util`
+      and `Foreign.Lua`: it is analogous to `run`, but allows to
+      run computations with a custom error conversion strategy.
+
+    - New function `runWithConverter` exported from
+      `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`; like
+      `run'`, but takes a custom state.
+
+    - New function `unsafeRunWith` exported from
+      `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`; runs a
+      computation without proper error handling.
+
+    - New function `errorConversion` exported from
+      `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`: extract
+      the error conversion strategy from the Lua type.
+
+    - New function `throwErrorAsException` exported from
+      `Foreign.Lua.Core.Error` and `Foreign.Lua.Core`: throws a
+      Lua error as Haskell exception, using the current error
+      conversion strategy.
+
+- Function `runWith` is moved from module `Foreign.Lua.Core` to
+  `Foreign.Lua.Util`.
+
+- The module `Foreign.Lua.Utf8` is now exported.
+
 
 ### 1.0.3.2
 
diff --git a/benchmark/benchmark-hslua.hsc b/benchmark/benchmark-hslua.hsc
--- a/benchmark/benchmark-hslua.hsc
+++ b/benchmark/benchmark-hslua.hsc
@@ -1,5 +1,5 @@
 {-
-Copyright © 2018 Albert Krewinkel
+Copyright © 2018-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/cbits/error-conversion/error-conversion.c b/cbits/error-conversion/error-conversion.c
--- a/cbits/error-conversion/error-conversion.c
+++ b/cbits/error-conversion/error-conversion.c
@@ -12,6 +12,17 @@
 }
 
 /*
+** Marks the occurence of an error; the returned value should be used as
+** the error message.
+*/
+int hslua_error(lua_State *L)
+{
+  hslua_pushhaskellerr(L);
+  lua_insert(L, -2);
+  return 2;
+}
+
+/*
 ** Checks whether the object at the given index is a Haskell error.
 */
 int hslua_is_haskell_error(lua_State *L, int idx) {
diff --git a/cbits/error-conversion/error-conversion.h b/cbits/error-conversion/error-conversion.h
--- a/cbits/error-conversion/error-conversion.h
+++ b/cbits/error-conversion/error-conversion.h
@@ -1,6 +1,8 @@
 #include "lua.h"
 #include "lauxlib.h"
 
+int hslua_error(lua_State *L);
+
 int hslua_call_hs(lua_State *L);
 
 int hslua_userdata_gc(lua_State *L);
diff --git a/hslua.cabal b/hslua.cabal
--- a/hslua.cabal
+++ b/hslua.cabal
@@ -1,5 +1,5 @@
 name:                hslua
-version:             1.0.3.2
+version:             1.1.0
 synopsis:            Bindings to Lua, an embeddable scripting language
 description:         HsLua provides bindings, wrappers, types, and helper
                      functions to bridge Haskell and <https://www.lua.org/ Lua>.
@@ -18,7 +18,7 @@
 maintainer:          albert+hslua@zeitkraut.de
 copyright:           © 2007–2012 Gracjan Polak
                      © 2012–2016 Ömer Sinan Ağacan
-                     © 2016–2019 Albert Krewinkel
+                     © 2016–2020 Albert Krewinkel
 category:            Foreign
 build-type:          Simple
 extra-source-files:  cbits/lua-5.3.5/*.h
@@ -29,8 +29,12 @@
                      CHANGELOG.md
                      test/lua/*.lua
 cabal-version:       >=1.10
-tested-with:         GHC == 7.10.3, GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.3
-                   , GHC == 8.6.1
+tested-with:         GHC == 7.10.3
+                   , GHC == 8.0.2
+                   , GHC == 8.2.2
+                   , GHC == 8.4.3
+                   , GHC == 8.6.5
+                   , GHC == 8.8.3
 
 source-repository head
   type:                git
@@ -95,15 +99,14 @@
                      , Foreign.Lua.Types.Peekable
                      , Foreign.Lua.Types.Pushable
                      , Foreign.Lua.Userdata
+                     , Foreign.Lua.Utf8
                      , Foreign.Lua.Util
-  other-modules:       Foreign.Lua.Utf8
-                     , Foreign.Lua.Core.Auxiliary
+  other-modules:       Foreign.Lua.Core.Auxiliary
                      , Foreign.Lua.Core.Functions
   build-depends:       base                 >= 4.8    && < 5
                      , bytestring           >= 0.10.2 && < 0.11
                      , containers           >= 0.5    && < 0.7
                      , exceptions           >= 0.8    && < 0.11
-                     , fail                 >= 4.9    && < 5
                      , mtl                  >= 2.2    && < 2.3
                      , text                 >= 1.0    && < 1.3
   hs-source-dirs:      src
@@ -189,7 +192,15 @@
   if flag(hardcode-reg-keys)
     cpp-options:         -DHARDCODE_REG_KEYS
 
+  if !impl(ghc >= 8.0)
+    build-depends:       fail                 >= 4.9    && < 5
+                       , semigroups           >= 0.18   && < 0.20
 
+  if impl(ghc < 8.8)
+    build-depends:       base-compat          >= 0.10
+    hs-source-dirs:      prelude
+    other-modules:       Prelude
+
 test-suite test-hslua
   type:                exitcode-stdio-1.0
   main-is:             test-hslua.hs
@@ -213,7 +224,6 @@
                      , bytestring           >= 0.10.2 && < 0.11
                      , containers           >= 0.5    && < 0.7
                      , exceptions           >= 0.8    && < 0.11
-                     , fail                 >= 4.9    && < 5
                      , mtl                  >= 2.2    && < 2.3
                      , text                 >= 1.0    && < 1.3
                      -- for testing
@@ -223,6 +233,15 @@
                      , tasty                >= 0.11
                      , tasty-hunit          >= 0.9
                      , tasty-quickcheck     >= 0.8
+
+  if impl(ghc < 8.0)
+    build-depends:       fail                 >= 4.9    && < 5
+                       , semigroups           >= 0.18   && < 0.20
+  if impl(ghc < 8.8)
+    build-depends:       base-compat          >= 0.10
+    hs-source-dirs:      prelude
+    other-modules:       Prelude
+
 
 benchmark benchmark-hslua
   type:                exitcode-stdio-1.0
diff --git a/prelude/Prelude.hs b/prelude/Prelude.hs
new file mode 100644
--- /dev/null
+++ b/prelude/Prelude.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE CPP #-}
+module Prelude (
+    module Prelude.Compat
+  , Semigroup (..)
+)
+where
+
+import Prelude.Compat
+import Data.Semigroup (Semigroup ((<>)))
diff --git a/src/Foreign/Lua.hs b/src/Foreign/Lua.hs
--- a/src/Foreign/Lua.hs
+++ b/src/Foreign/Lua.hs
@@ -1,7 +1,7 @@
 {-
 Copyright © 2007-2012 Gracjan Polak
 Copyright © 2012-2016 Ömer Sinan Ağacan
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -25,7 +25,7 @@
 Module      : Foreign.Lua
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -62,7 +62,9 @@
   , registerHaskellFunction
   -- * Utility functions and types
   , run
+  , run'
   , runEither
+  , runWith
   , getglobal'
   , setglobal'
   , raiseError
diff --git a/src/Foreign/Lua/Core.hs b/src/Foreign/Lua/Core.hs
--- a/src/Foreign/Lua/Core.hs
+++ b/src/Foreign/Lua/Core.hs
@@ -2,7 +2,7 @@
 Module      : Foreign.Lua.Core
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -16,9 +16,14 @@
 module Foreign.Lua.Core (
   -- * Lua Computations
     Lua (..)
-  , runWith
+  , runWithConverter
+  , unsafeRunWith
   , liftIO
   , state
+  , LuaEnvironment (..)
+  , ErrorConversion (..)
+  , errorConversion
+  , unsafeErrorConversion
   -- * Lua API types
   , CFunction
   , Lua.Integer (..)
@@ -173,7 +178,11 @@
   , catchException
   , withExceptionMessage
   , try
+  , throwMessage
+  , errorMessage
+  , throwErrorAsException
   , throwTopMessage
+  , throwTopMessageWithState
   ) where
 
 import Prelude hiding (EQ, LT, compare, concat, error)
diff --git a/src/Foreign/Lua/Core/Auxiliary.hsc b/src/Foreign/Lua/Core/Auxiliary.hsc
--- a/src/Foreign/Lua/Core/Auxiliary.hsc
+++ b/src/Foreign/Lua/Core/Auxiliary.hsc
@@ -4,7 +4,7 @@
 Module      : Foreign.Lua.Core.Auxiliary
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -36,10 +36,9 @@
 
 import Control.Exception (IOException, try)
 import Data.ByteString (ByteString)
-import Data.Monoid ((<>))
 import Foreign.C ( CChar, CInt (CInt), CSize (CSize), CString, withCString )
 import Foreign.Lua.Core.Constants (multret, registryindex)
-import Foreign.Lua.Core.Error (hsluaErrorRegistryField, throwTopMessage)
+import Foreign.Lua.Core.Error (hsluaErrorRegistryField)
 import Foreign.Lua.Core.Types (Lua, Reference, StackIndex, Status, liftLua)
 import Foreign.Marshal.Alloc (alloca)
 import Foreign.Ptr
@@ -250,7 +249,7 @@
 newstate :: IO Lua.State
 newstate = do
   l <- luaL_newstate
-  Lua.runWith l $ do
+  Lua.unsafeRunWith l $ do
     Lua.createtable 0 0
     Lua.setfield registryindex hsluaErrorRegistryField
     return l
@@ -288,13 +287,16 @@
 -- calls the corresponding metamethod with the value as argument, and uses the
 -- result of the call as its result.
 tostring' :: StackIndex -> Lua B.ByteString
-tostring' n = liftLua $ \l -> alloca $ \lenPtr -> do
-  cstr <- hsluaL_tolstring l n lenPtr
-  if cstr == nullPtr
-    then Lua.runWith l throwTopMessage
-    else do
-      cstrLen <- Storable.peek lenPtr
-      B.packCStringLen (cstr, fromIntegral cstrLen)
+tostring' n = do
+  l <- Lua.state
+  e2e <- Lua.errorToException <$> Lua.errorConversion
+  Lua.liftIO $ alloca $ \lenPtr -> do
+    cstr <- hsluaL_tolstring l n lenPtr
+    if cstr == nullPtr
+      then e2e l
+      else do
+        cstrLen <- Storable.peek lenPtr
+        B.packCStringLen (cstr, fromIntegral cstrLen)
 
 foreign import ccall safe "error-conversion.h hsluaL_tolstring"
   hsluaL_tolstring :: Lua.State -> StackIndex -> Ptr CSize -> IO (Ptr CChar)
diff --git a/src/Foreign/Lua/Core/Constants.hsc b/src/Foreign/Lua/Core/Constants.hsc
--- a/src/Foreign/Lua/Core/Constants.hsc
+++ b/src/Foreign/Lua/Core/Constants.hsc
@@ -2,7 +2,7 @@
 Module      : Foreign.Lua.Core.Constants
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
diff --git a/src/Foreign/Lua/Core/Error.hs b/src/Foreign/Lua/Core/Error.hs
--- a/src/Foreign/Lua/Core/Error.hs
+++ b/src/Foreign/Lua/Core/Error.hs
@@ -1,9 +1,10 @@
 {-# LANGUAGE DeriveDataTypeable         #-}
 {-# LANGUAGE OverloadedStrings          #-}
+{-# LANGUAGE ScopedTypeVariables        #-}
 {-# OPTIONS_GHC -fno-warn-orphans       #-}
 {-|
 Module      : Foreign.Lua.Core.Error
-Copyright   : © 2017-2019 Albert Krewinkel
+Copyright   : © 2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -16,12 +17,16 @@
   , catchException
   , throwException
   , withExceptionMessage
+  , throwErrorAsException
   , throwTopMessage
+  , throwTopMessageWithState
+  , errorMessage
   , try
     -- * Helpers for hslua C wrapper functions.
   , Failable (..)
   , fromFailable
   , throwOnError
+  , throwMessage
   , boolFromFailable
     -- * Signaling errors to Lua
   , hsluaErrorRegistryField
@@ -29,7 +34,7 @@
 
 import Control.Applicative (Alternative (..))
 import Data.Typeable (Typeable)
-import Foreign.C (CChar, CInt (CInt), CSize)
+import Foreign.C (CChar, CInt (CInt), CSize (CSize))
 import Foreign.Marshal.Alloc (alloca)
 import Foreign.Ptr (Ptr, nullPtr)
 import Foreign.Lua.Core.Types (Lua, StackIndex, fromLuaBool)
@@ -38,6 +43,7 @@
 import qualified Control.Monad.Catch as Catch
 import qualified Data.ByteString as B
 import qualified Data.ByteString.Char8 as Char8
+import qualified Data.ByteString.Unsafe as B
 import qualified Foreign.Storable as Storable
 import qualified Foreign.Lua.Core.Types as Lua
 import qualified Foreign.Lua.Utf8 as Utf8
@@ -73,18 +79,44 @@
 try = Catch.try
 {-# INLINABLE try #-}
 
-instance Alternative Lua where
-  empty = throwException "empty"
-  x <|> y = either (const y) return =<< try x
+-- | Convert a Lua error into a Haskell exception. The error message is
+-- expected to be at the top of the stack.
+throwErrorAsException :: Lua a
+throwErrorAsException = do
+  f <- Lua.errorToException <$> Lua.errorConversion
+  l <- Lua.state
+  Lua.liftIO (f l)
 
--- | Convert the object at the top of the stack into a string and throw it as
--- an @'Exception'@.
+-- | Alias for `throwErrorAsException`; will be deprecated in the next
+-- mayor release.
 throwTopMessage :: Lua a
-throwTopMessage = do
-  l <- Lua.state
+throwTopMessage = throwErrorAsException
+
+instance Alternative Lua where
+  empty = throwMessage "empty"
+  x <|> y = do
+    alt <- Lua.alternative <$> Lua.errorConversion
+    x `alt` y
+
+-- | Convert the object at the top of the stack into a string and throw
+-- it as a HsLua @'Exception'@.
+--
+-- This function serves as the default to convert Lua errors to Haskell
+-- exceptions.
+throwTopMessageWithState :: Lua.State -> IO a
+throwTopMessageWithState l = do
   msg <- Lua.liftIO (errorMessage l)
-  throwException (Utf8.toString msg)
+  Catch.throwM $ Exception (Utf8.toString msg)
 
+-- | Helper function which uses proper error-handling to throw an
+-- exception with the given message.
+throwMessage :: String -> Lua a
+throwMessage msg = do
+  Lua.liftLua $ \l ->
+    B.unsafeUseAsCStringLen (Utf8.fromString msg) $ \(msgPtr, z) ->
+      lua_pushlstring l msgPtr (fromIntegral z)
+  Lua.errorConversion >>= Lua.liftLua . Lua.errorToException
+
 -- | Retrieve and pop the top object as an error message. This is very similar
 -- to tostring', but ensures that we don't recurse if getting the message
 -- failed.
@@ -105,6 +137,9 @@
 
 foreign import capi unsafe "lua.h lua_pop"
   lua_pop :: Lua.State -> CInt -> IO ()
+
+foreign import capi unsafe "lua.h lua_pushlstring"
+  lua_pushlstring :: Lua.State -> Ptr CChar -> CSize -> IO ()
 
 -- | Registry field under which the special HsLua error indicator is stored.
 hsluaErrorRegistryField :: String
diff --git a/src/Foreign/Lua/Core/Functions.hs b/src/Foreign/Lua/Core/Functions.hs
--- a/src/Foreign/Lua/Core/Functions.hs
+++ b/src/Foreign/Lua/Core/Functions.hs
@@ -2,7 +2,7 @@
 Module      : Foreign.Lua.Core.Functions
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -21,7 +21,6 @@
 
 import Control.Monad
 import Data.ByteString (ByteString)
-import Data.Monoid ((<>))
 import Data.Maybe (fromMaybe)
 import Foreign.Lua.Core.Constants
 import Foreign.Lua.Core.Error
@@ -40,7 +39,8 @@
 -- Helper functions
 --
 
--- | Execute an action only if the given index is a table. Throw an error otherwise.
+-- | Execute an action only if the given index is a table. Throw an
+-- error otherwise.
 ensureTable :: StackIndex -> (Lua.State -> IO ()) -> Lua ()
 ensureTable idx ioOp = do
   isTbl <- istable idx
@@ -48,7 +48,7 @@
     then liftLua ioOp
     else do
       tyName <- ltype idx >>= typename
-      throwException ("table expected, got " <> tyName)
+      throwMessage ("table expected, got " <> tyName)
 
 --
 -- API functions
@@ -193,10 +193,7 @@
 -- `lua_error` function from Lua C API because it's never safe to use. (see
 -- [Error handling in hslua](#g:1) for details)
 error :: Lua NumResults
-error = do
-  getfield registryindex hsluaErrorRegistryField
-  insert (-2)
-  return 2
+error = liftLua hslua_error
 
 -- |  Controls the garbage collector.
 --
diff --git a/src/Foreign/Lua/Core/RawBindings.hsc b/src/Foreign/Lua/Core/RawBindings.hsc
--- a/src/Foreign/Lua/Core/RawBindings.hsc
+++ b/src/Foreign/Lua/Core/RawBindings.hsc
@@ -3,7 +3,7 @@
 Module      : Foreign.Lua.Core.RawBindings
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -323,9 +323,15 @@
 ------------------------------------------------------------------------------
 -- * Miscellaneous functions
 
--- lua_error is unsafe in a haskell context and hence not supported.
+-- lua_error is unsafe, use hslua_error instead.
 -- lua_next is unsafe, use hslua_next instead.
 -- lua_concat is unsafe (may trigger a longjmp), use hslua_concat instead.
+
+-- | Replacement for <https://lua.org/manual/5.3/manual.html#lua_error \
+-- @lua_error@>; it uses the HsLua error signaling convention instead of raw
+-- @longjmp@.
+foreign import ccall "error-conversion.h hslua_error"
+  hslua_error :: Lua.State -> IO NumResults
 
 -- | Wrapper around <https://lua.org/manual/5.3/manual.html#lua_next \
 -- @lua_next@> which catches any @longjmp@s.
diff --git a/src/Foreign/Lua/Core/Types.hsc b/src/Foreign/Lua/Core/Types.hsc
--- a/src/Foreign/Lua/Core/Types.hsc
+++ b/src/Foreign/Lua/Core/Types.hsc
@@ -1,10 +1,11 @@
 {-# LANGUAGE DeriveGeneric              #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE RankNTypes                 #-}
 {-|
 Module      : Foreign.Lua.Core.Types
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -14,12 +15,17 @@
 -}
 module Foreign.Lua.Core.Types
   ( Lua (..)
+  , LuaEnvironment (..)
+  , ErrorConversion (..)
+  , errorConversion
   , State (..)
   , Reader
   , liftLua
   , liftLua1
   , state
-  , runWith
+  , runWithConverter
+  , unsafeRunWith
+  , unsafeErrorConversion
   , GCCONTROL (..)
   , Type (..)
   , TypeCode (..)
@@ -59,17 +65,38 @@
 import Prelude hiding (Integer, EQ, LT)
 
 import Control.Monad.Catch (MonadCatch, MonadMask, MonadThrow)
-import Control.Monad.Reader (ReaderT (..), MonadReader, MonadIO, ask, liftIO)
+import Control.Monad.Reader (ReaderT (..), MonadReader, MonadIO, asks, liftIO)
 import Data.Int (#{type LUA_INTEGER})
 import Foreign.C (CChar, CInt, CSize)
 import Foreign.Ptr (FunPtr, Ptr)
 import Foreign.Storable (Storable)
 import GHC.Generics (Generic)
 
+-- | Define the ways in which exceptions and errors are handled.
+data ErrorConversion = ErrorConversion
+  { errorToException :: forall a . State -> IO a
+    -- ^ Translate Lua errors to Haskell exceptions
+  , addContextToException :: forall a . String -> Lua a -> Lua a
+    -- ^ Add information on the current context to an exception.
+  , alternative :: forall a . Lua a -> Lua a -> Lua a
+    -- ^ Runs the second computation only if the first fails; returns
+    -- the result of the first successful computation, if any.
+  , exceptionToError :: Lua NumResults -> Lua NumResults
+    -- ^ Translate Haskell exceptions to Lua errors
+  }
+
+-- | Environment in which Lua computations are evaluated.
+data LuaEnvironment = LuaEnvironment
+  { luaEnvErrorConversion :: ErrorConversion
+    -- ^ Functions for error and exception handling and conversion
+  , luaEnvState :: State
+    -- ^ Lua interpreter state
+  }
+
 -- | A Lua computation. This is the base type used to run Lua programs of any
 -- kind. The Lua state is handled automatically, but can be retrieved via
 -- @'state'@.
-newtype Lua a = Lua { unLua :: ReaderT State IO a }
+newtype Lua a = Lua { unLua :: ReaderT LuaEnvironment IO a }
   deriving
     ( Applicative
     , Functor
@@ -77,26 +104,45 @@
     , MonadCatch
     , MonadIO
     , MonadMask
-    , MonadReader State
+    , MonadReader LuaEnvironment
     , MonadThrow
     )
 
--- | Turn a function of typ @Lua.State -> IO a@ into a monadic lua operation.
+-- | Turn a function of typ @Lua.State -> IO a@ into a monadic Lua operation.
 liftLua :: (State -> IO a) -> Lua a
 liftLua f = state >>= liftIO . f
 
--- | Turn a function of typ @Lua.State -> a -> IO b@ into a monadic lua operation.
+-- | Turn a function of typ @Lua.State -> a -> IO b@ into a monadic Lua operation.
 liftLua1 :: (State -> a -> IO b) -> a -> Lua b
 liftLua1 f x = liftLua $ \l -> f l x
 
--- | Get the lua state of this lua computation.
+-- | Get the Lua state of this Lua computation.
 state :: Lua State
-state = ask
+state = asks luaEnvState
 
--- | Run lua computation with custom lua state. Errors are left unhandled, the
--- caller of this function is responsible to catch lua errors.
-runWith :: State -> Lua a -> IO a
-runWith l s = runReaderT (unLua s) l
+-- | Get the error-to-exception function.
+errorConversion :: Lua ErrorConversion
+errorConversion = asks luaEnvErrorConversion
+
+-- | Run Lua computation with the given Lua state and error-to-exception
+-- converter. Any resulting exceptions are left unhandled.
+runWithConverter :: ErrorConversion -> State -> Lua a -> IO a
+runWithConverter e2e l s =
+  runReaderT (unLua s) (LuaEnvironment e2e l)
+
+-- | Run the given operation, but crash if any Haskell exceptions occur.
+unsafeRunWith :: State -> Lua a -> IO a
+unsafeRunWith = runWithConverter unsafeErrorConversion
+
+-- | Unsafe @'ErrorConversion'@; no proper error handling is attempted,
+-- any error leads to a crash.
+unsafeErrorConversion :: ErrorConversion
+unsafeErrorConversion = ErrorConversion
+  { errorToException = const (error "An unrecoverable Lua error occured.")
+  , addContextToException = const id
+  , alternative = const
+  , exceptionToError = id
+  }
 
 -- | An opaque structure that points to a thread and indirectly (through the
 -- thread) to the whole state of a Lua interpreter. The Lua library is fully
diff --git a/src/Foreign/Lua/FunctionCalling.hsc b/src/Foreign/Lua/FunctionCalling.hsc
--- a/src/Foreign/Lua/FunctionCalling.hsc
+++ b/src/Foreign/Lua/FunctionCalling.hsc
@@ -6,7 +6,7 @@
 Module      : Foreign.Lua.FunctionCalling
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -26,11 +26,11 @@
   , freeCFunction
   , newCFunction
   , pushHaskellFunction
+  , pushPreCFunction
   , registerHaskellFunction
   ) where
 
 import Data.ByteString (ByteString)
-import Data.Monoid ((<>))
 import Foreign.C (CInt (..))
 import Foreign.Lua.Core as Lua
 import Foreign.Lua.Types
@@ -87,13 +87,18 @@
 -- > toHaskellFunction (myFun `catchM` (\e -> raiseError (e :: FooException)))
 --
 toHaskellFunction :: ToHaskellFunction a => a -> HaskellFunction
-toHaskellFunction a = toHsFun 1 a `catchException` \(Lua.Exception msg) ->
-  raiseError ("Error during function call: " <> msg)
+toHaskellFunction a = do
+  errConv <- Lua.errorConversion
+  let ctx = "Error during function call: "
+  Lua.exceptionToError errConv . Lua.addContextToException errConv ctx $
+    toHsFun 1 a
 
--- | Create new foreign Lua function. Function created can be called
--- by Lua engine. Remeber to free the pointer with @freecfunction@.
+-- | Create new foreign Lua function. Function created can be called by
+-- the Lua engine. Remeber to free the pointer with @freecfunction@.
 newCFunction :: ToHaskellFunction a => a -> Lua CFunction
-newCFunction = liftIO . mkWrapper . flip runWith . toHaskellFunction
+newCFunction f = do
+  e2e <- Lua.errorConversion
+  liftIO . mkWrapper . flip (Lua.runWithConverter e2e) . toHaskellFunction $ f
 
 -- | Turn a @'PreCFunction'@ into an actual @'CFunction'@.
 foreign import ccall "wrapper"
@@ -140,7 +145,8 @@
 -- or by returning the result of @'Lua.error'@.
 pushHaskellFunction :: ToHaskellFunction a => a -> Lua ()
 pushHaskellFunction hsFn = do
-  pushPreCFunction . flip runWith $ toHaskellFunction hsFn
+  errConv <- Lua.errorConversion
+  pushPreCFunction . flip (runWithConverter errConv) $ toHaskellFunction hsFn
   -- Convert userdata object into a CFuntion.
   pushcclosure hslua_call_hs_ptr 1
 
@@ -155,7 +161,7 @@
 -- | Converts a pre C function to a Lua function and pushes it to the stack.
 --
 -- Pre C functions collect parameters from the stack and return
--- a `CInt` that represents number of return values left in the stack.
+-- a `CInt` that represents number of return values left on the stack.
 pushPreCFunction :: PreCFunction -> Lua ()
 pushPreCFunction f =
   let pushMetatable = ensureUserdataMetatable hsLuaFunctionName $ do
@@ -168,11 +174,12 @@
 -- as a C function and then re-imported in order to get a C function pointer.
 hslua_call_wrapped_hs_fun :: Lua.State -> IO NumResults
 hslua_call_wrapped_hs_fun l = do
-  mbFn <- runWith l (toAnyWithName stackBottom hsLuaFunctionName
-                     <* remove stackBottom)
+  mbFn <- unsafeRunWith l (toAnyWithName stackBottom hsLuaFunctionName
+                           <* remove stackBottom)
   case mbFn of
-    Nothing -> runWith l (raiseError ("Could not call function" :: ByteString))
     Just fn -> fn l
+    Nothing -> unsafeRunWith l
+               (raiseError ("Could not call function" :: ByteString))
 
 foreign export ccall hslua_call_wrapped_hs_fun :: PreCFunction
 foreign import ccall "&hslua_call_wrapped_hs_fun"
diff --git a/src/Foreign/Lua/Module.hs b/src/Foreign/Lua/Module.hs
--- a/src/Foreign/Lua/Module.hs
+++ b/src/Foreign/Lua/Module.hs
@@ -1,6 +1,6 @@
 {-|
 Module      : Foreign.Lua.Module
-Copyright   : © 2019 Albert Krewinkel
+Copyright   : © 2019-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <albert+hslua@zeitkraut.de>
 Stability   : alpha
diff --git a/src/Foreign/Lua/Types.hs b/src/Foreign/Lua/Types.hs
--- a/src/Foreign/Lua/Types.hs
+++ b/src/Foreign/Lua/Types.hs
@@ -1,6 +1,6 @@
 {-|
 Module      : Foreign.Lua.Types
-Copyright   : © 2017-2019 Albert Krewinkel
+Copyright   : © 2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
diff --git a/src/Foreign/Lua/Types/Peekable.hs b/src/Foreign/Lua/Types/Peekable.hs
--- a/src/Foreign/Lua/Types/Peekable.hs
+++ b/src/Foreign/Lua/Types/Peekable.hs
@@ -6,7 +6,7 @@
 Module      : Foreign.Lua.Types.Peekable
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -24,7 +24,6 @@
 import Data.ByteString (ByteString)
 import Data.Map (Map, fromList)
 import Data.Set (Set)
-import Data.Monoid ((<>))
 import Foreign.Lua.Core as Lua
 import Foreign.Ptr (Ptr)
 import Text.Read (readMaybe)
@@ -65,7 +64,7 @@
   actualValue <- Utf8.toString <$> tostring' idx <* pop 1
   let msg = "expected " <> expected <> ", got '" <>
             actualValue <> "' (" <> actualType <> ")"
-  Lua.throwException msg
+  Lua.throwMessage msg
 
 -- | A value that can be read from the Lua stack.
 class Peekable a where
@@ -192,8 +191,11 @@
             -- removes the value, keeps the key
     else return Nothing
 
+-- | Specify a name for the context in which a computation is run. The name is
+-- added to the error message in case of an exception.
 inContext :: String -> Lua a -> Lua a
-inContext ctx = Lua.withExceptionMessage (ctx <>)
+inContext ctx op = Lua.errorConversion >>= \ec ->
+  Lua.addContextToException ec ctx op
 
 --
 -- Tuples
diff --git a/src/Foreign/Lua/Types/Pushable.hs b/src/Foreign/Lua/Types/Pushable.hs
--- a/src/Foreign/Lua/Types/Pushable.hs
+++ b/src/Foreign/Lua/Types/Pushable.hs
@@ -5,7 +5,7 @@
 Module      : Foreign.Lua.Types.Pushable
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
diff --git a/src/Foreign/Lua/Userdata.hs b/src/Foreign/Lua/Userdata.hs
--- a/src/Foreign/Lua/Userdata.hs
+++ b/src/Foreign/Lua/Userdata.hs
@@ -3,7 +3,7 @@
 Module      : Foreign.Lua.Userdata
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
diff --git a/src/Foreign/Lua/Utf8.hs b/src/Foreign/Lua/Utf8.hs
--- a/src/Foreign/Lua/Utf8.hs
+++ b/src/Foreign/Lua/Utf8.hs
@@ -1,6 +1,6 @@
 {-|
 Module      : Foreign.Lua.Utf8
-Copyright   : © 2018-2019 Albert Krewinkel
+Copyright   : © 2018-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -40,5 +40,3 @@
 fromText :: Text -> ByteString
 fromText = TextEncoding.encodeUtf8
 {-# INLINABLE fromText #-}
-
-    -- Text.unpack (Encoding.decodeUtf8With TextError.lenientDecode msg)
diff --git a/src/Foreign/Lua/Util.hs b/src/Foreign/Lua/Util.hs
--- a/src/Foreign/Lua/Util.hs
+++ b/src/Foreign/Lua/Util.hs
@@ -2,7 +2,7 @@
 Module      : Foreign.Lua.Util
 Copyright   : © 2007–2012 Gracjan Polak,
                 2012–2016 Ömer Sinan Ağacan,
-                2017-2019 Albert Krewinkel
+                2017-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <tarleb+hslua@zeitkraut.de>
 Stability   : beta
@@ -14,10 +14,13 @@
   ( getglobal'
   , setglobal'
   , run
+  , run'
   , runEither
   , raiseError
   , Optional (Optional, fromOptional)
-  -- * getting values
+    -- * Default error handling
+  , runWith
+    -- * getting values
   , peekEither
   , peekRead
   , popValue
@@ -38,14 +41,40 @@
 -- All exceptions are passed through; error handling is the responsibility of
 -- the caller.
 run :: Lua a -> IO a
-run = (Lua.newstate `bracket` Lua.close) . flip Lua.runWith . Catch.mask_
+run = (Lua.newstate `bracket` Lua.close) . flip runWith . Catch.mask_
 
+-- | Run Lua computation using the default HsLua state as starting point.
+-- Conversion from Lua errors to Haskell exceptions can be controlled through
+-- @'Lua.ErrorConversion'@.
+run' :: Lua.ErrorConversion -> Lua a -> IO a
+run' ec = (Lua.newstate `bracket` Lua.close) .
+  flip (Lua.runWithConverter ec) . Catch.mask_
+
 -- | Run the given Lua computation; exceptions raised in haskell code are
 -- caught, but other exceptions (user exceptions raised in haskell, unchecked
 -- type errors, etc.) are passed through.
-runEither :: Lua a -> IO (Either Lua.Exception a)
+runEither :: Catch.Exception e => Lua a -> IO (Either e a)
 runEither = try . run
 
+-- | Run Lua computation with the given Lua state and the default
+-- error-to-exception converter (@'throwTopStringAsException'@). Exception
+-- handling is left to the caller.
+runWith :: Lua.State -> Lua a -> IO a
+runWith = Lua.runWithConverter defaultErrorConversion
+
+-- | Conversions between Lua errors and Haskell exceptions; only deals with
+-- @'Lua.Exception'@s.
+defaultErrorConversion :: Lua.ErrorConversion
+defaultErrorConversion = Lua.ErrorConversion
+  { Lua.errorToException = Lua.throwTopMessageWithState
+  , Lua.addContextToException = Lua.withExceptionMessage . (++)
+  , Lua.alternative = \x y -> Lua.try x >>= \case
+      Left _   -> y
+      Right x' -> return x'
+  , Lua.exceptionToError = (`Lua.catchException` \ (Lua.Exception msg) ->
+                            raiseError msg)
+  }
+
 -- | Like @getglobal@, but knows about packages and nested tables. E.g.
 --
 -- > getglobal' "math.sin"
@@ -126,6 +155,8 @@
 
 -- | Try to convert the value at the given stack index to a Haskell value.
 -- Returns @Left@ with an error message on failure.
+--
+-- WARNING: this is not save to use with custom error handling!
 peekEither :: Peekable a => StackIndex -> Lua (Either String a)
 peekEither idx = either (Left . Lua.exceptionMessage) Right <$>
                  Lua.try (Lua.peek idx)
diff --git a/test/Foreign/Lua/CoreTests.hs b/test/Foreign/Lua/CoreTests.hs
--- a/test/Foreign/Lua/CoreTests.hs
+++ b/test/Foreign/Lua/CoreTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -23,7 +23,7 @@
 {-# OPTIONS_GHC -fno-warn-deprecations #-}
 {-|
 Module      :  Foreign.Lua.CoreTests
-Copyright   :  © 2017-2019 Albert Krewinkel
+Copyright   :  © 2017-2020 Albert Krewinkel
 License     :  MIT
 
 Maintainer  :  Albert Krewinkel <tarleb+hslua@zeitkraut.de>
@@ -38,7 +38,6 @@
 
 import Control.Monad (forM_)
 import Data.Maybe (fromMaybe)
-import Data.Monoid ((<>))
 import Foreign.Lua as Lua
 import Test.HsLua.Arbitrary ()
 import Test.HsLua.Util ( (?:), (=:), shouldBeErrorMessageOf, shouldBeResultOf
diff --git a/test/Foreign/Lua/FunctionCallingTests.hs b/test/Foreign/Lua/FunctionCallingTests.hs
--- a/test/Foreign/Lua/FunctionCallingTests.hs
+++ b/test/Foreign/Lua/FunctionCallingTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -25,7 +25,6 @@
 
 import Control.Monad (forM_)
 import Data.ByteString.Char8 as Char8
-import Data.Monoid ((<>))
 import Foreign.Lua (Lua)
 import Test.HsLua.Util ( (=:), pushLuaExpr, shouldBeErrorMessageOf
                        , shouldBeResultOf )
diff --git a/test/Foreign/Lua/ModuleTests.hs b/test/Foreign/Lua/ModuleTests.hs
--- a/test/Foreign/Lua/ModuleTests.hs
+++ b/test/Foreign/Lua/ModuleTests.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-|
 Module      : Foreign.Lua.ModuleTests
-Copyright   : © 2019 Albert Krewinkel
+Copyright   : © 2019-2020 Albert Krewinkel
 License     : MIT
 Maintainer  : Albert Krewinkel <albert+hslua@zeitkraut.de>
 Stability   : alpha
diff --git a/test/Foreign/Lua/Types/PeekableTests.hs b/test/Foreign/Lua/Types/PeekableTests.hs
--- a/test/Foreign/Lua/Types/PeekableTests.hs
+++ b/test/Foreign/Lua/Types/PeekableTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -22,7 +22,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-|
 Module      :  Foreign.Lua.Types.PeekableTests
-Copyright   :  © 2017-2019 Albert Krewinkel
+Copyright   :  © 2017-2020 Albert Krewinkel
 License     :  MIT
 
 Maintainer  :  Albert Krewinkel <tarleb+hslua@zeitkraut.de>
diff --git a/test/Foreign/Lua/Types/PushableTests.hs b/test/Foreign/Lua/Types/PushableTests.hs
--- a/test/Foreign/Lua/Types/PushableTests.hs
+++ b/test/Foreign/Lua/Types/PushableTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -22,7 +22,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-|
 Module      :  Foreign.Lua.Types.PushableTests
-Copyright   :  © 2017-2019 Albert Krewinkel
+Copyright   :  © 2017-2020 Albert Krewinkel
 License     :  MIT
 
 Maintainer  :  Albert Krewinkel <tarleb+hslua@zeitkraut.de>
diff --git a/test/Foreign/Lua/TypesTests.hs b/test/Foreign/Lua/TypesTests.hs
--- a/test/Foreign/Lua/TypesTests.hs
+++ b/test/Foreign/Lua/TypesTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/test/Foreign/Lua/UserdataTests.hs b/test/Foreign/Lua/UserdataTests.hs
--- a/test/Foreign/Lua/UserdataTests.hs
+++ b/test/Foreign/Lua/UserdataTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2018-2019 Albert Krewinkel
+Copyright © 2018-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/test/Foreign/Lua/UtilTests.hs b/test/Foreign/Lua/UtilTests.hs
--- a/test/Foreign/Lua/UtilTests.hs
+++ b/test/Foreign/Lua/UtilTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2018-2019 Albert Krewinkel
+Copyright © 2018-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -58,11 +58,11 @@
   , testGroup "runEither"
     [ "Lua errors are caught" =:
       isLeft `shouldHoldForResultOf`
-        liftIO (runEither (push True *> peek (-1) :: Lua String))
+        liftIO (runEither' (push True *> peek (-1) :: Lua String))
 
     , "error-less code gives 'Right'" =:
       isRight `shouldHoldForResultOf`
-        liftIO (runEither (push True *> peek (-1) :: Lua Bool))
+        liftIO (runEither' (push True *> peek (-1) :: Lua Bool))
     ]
 
   , testGroup "peekEither"
@@ -105,3 +105,7 @@
         return (p1 == p2)
     ]
   ]
+
+
+runEither' :: Lua a -> IO (Either Lua.Exception a)
+runEither' = runEither
diff --git a/test/Foreign/LuaTests.hs b/test/Foreign/LuaTests.hs
--- a/test/Foreign/LuaTests.hs
+++ b/test/Foreign/LuaTests.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -19,25 +19,31 @@
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 -}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-| Tests for HsLua -}
 module Foreign.LuaTests (tests) where
 
 import Prelude hiding (concat)
 
+import Control.Applicative (Alternative (..))
 import Data.ByteString (ByteString)
+import Data.Data (Typeable)
 import Data.Either (isLeft)
-import Data.Monoid ((<>))
 import Foreign.Lua as Lua
 import System.Mem (performMajorGC)
 import Test.HsLua.Util ( (=:), (?:), pushLuaExpr, shouldBeErrorMessageOf
                        , shouldHoldForResultOf)
 import Test.Tasty (TestTree, testGroup)
-import Test.Tasty.HUnit (assertBool, assertEqual, testCase)
+import Test.Tasty.HUnit ((@?=), assertBool, assertEqual, testCase)
 
+import qualified Control.Monad.Catch as Catch
 import qualified Data.ByteString.Char8 as Char8
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as T
+import qualified Foreign.Lua.Utf8 as Utf8
 
 -- | Specifications for Attributes parsing functions.
 tests :: TestTree
@@ -136,7 +142,8 @@
               then peek (-1)
               else throwException "Error in words function."
       in assertEqual "greeting function failed"
-          (Right ["Caffeine", "induced", "nonsense"]) =<< runEither comp
+          (Right ["Caffeine", "induced", "nonsense"])
+          =<< (runEither comp :: IO (Either Lua.Exception [String]))
 
     , testCase "pushing a C closure to and calling it from Lua" $
       -- Closures would usually be defined on the Haskell side, unless the
@@ -157,7 +164,7 @@
             peek (-1)
 
       in assertEqual "greeting function failed" (Right "Hello, World!") =<<
-         runEither comp
+         (runEither comp :: IO (Either Lua.Exception String))
     ]
 
   , testGroup "error handling"
@@ -173,13 +180,97 @@
       `shouldBeErrorMessageOf` do
         openbase
         loadstring "return error('error message')" *> call 0 1
+
+    , let errTbl ="setmetatable({}, {__index = function(t, k) error(k) end})"
+      in testGroup "error conversion"
+      [ "throw custom exceptions" =: do
+          let comp = do
+                openlibs
+                pushLuaExpr errTbl
+                pushnumber 23
+                gettable (Lua.nthFromTop 2) :: Lua ()
+          result <- tryCustom comp
+          result @?= Left (ExceptionWithNumber 23)
+
+      , "catch custom exception in exposed function" =: do
+          let frob n = do
+                pushLuaExpr errTbl
+                pushnumber n
+                gettable (Lua.nthFromTop 2) :: Lua ()
+          result <- tryCustom $ do
+            openlibs
+            registerHaskellFunction "frob" frob
+            callFunc "frob" (Lua.Number 42) :: Lua ()
+          result @?= Left (ExceptionWithNumber 42)
+
+      , "pass exception through Lua" =: do
+          let frob = Catch.throwM (ExceptionWithMessage "borked") :: Lua ()
+          result <- tryCustom $ do
+            pushHaskellFunction frob
+            call 0 1
+          result @?= Left (ExceptionWithMessage "borked")
+
+      , "failing peek" =: do
+          let msg = "expected integer, got '1.1' (number)"
+          result <- tryCustom $ do
+            pushnumber 1.1
+            peek stackTop :: Lua Lua.Integer
+          result @?= Left (ExceptionWithMessage msg)
+
+      , "alternative" =: do
+          result <- tryCustom $ do
+            pushstring "NaN"
+            pushnumber 13.37
+            (<|>) (peek (nthFromTop 2) :: Lua Number)
+                  (peek stackTop :: Lua Number)
+          result @?= Right 13.37
+      ]
     ]
   ]
 
---------------------------------------------------------------------------------
+-------------------------------------------------------------------------------
 -- luaopen_* functions
 
 testOpen :: String -> Lua () -> TestTree
 testOpen lib openfn = testCase ("open" ++ lib) $
   assertBool "opening the library failed" =<<
   run (openfn *> istable (-1))
+
+
+-------------------------------------------------------------------------------
+-- Custom exception handling
+
+data CustomException =
+    ExceptionWithNumber Lua.Number
+  | ExceptionWithMessage String
+  deriving (Eq, Show, Typeable)
+
+instance Catch.Exception CustomException
+
+customErrorConversion :: Lua.ErrorConversion
+customErrorConversion = Lua.ErrorConversion
+  { errorToException = errorToCustomException
+  , addContextToException = const id
+  , alternative = customAlternative
+  , exceptionToError = flip Catch.catch $ \case
+      ExceptionWithMessage m -> raiseError (Utf8.fromString m)
+      ExceptionWithNumber n  -> raiseError n
+  }
+
+errorToCustomException :: Lua.State -> IO a
+errorToCustomException l = Lua.unsafeRunWith l $
+  Lua.tonumber Lua.stackTop >>= \case
+    Just num -> do
+      Lua.pop 1
+      Catch.throwM (ExceptionWithNumber num)
+    _        -> do
+      msg <- Lua.liftIO (Lua.errorMessage l)
+      Catch.throwM (ExceptionWithMessage (Utf8.toString msg))
+
+tryCustom :: Lua a -> IO (Either CustomException a)
+tryCustom = Catch.try . Lua.run' customErrorConversion
+
+customAlternative :: Lua a -> Lua a -> Lua a
+customAlternative x y = Catch.try x >>= \case
+  Left (_ :: CustomException) -> y
+  Right x' -> return x'
diff --git a/test/Test/HsLua/Arbitrary.hs b/test/Test/HsLua/Arbitrary.hs
--- a/test/Test/HsLua/Arbitrary.hs
+++ b/test/Test/HsLua/Arbitrary.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/test/Test/HsLua/Util.hs b/test/Test/HsLua/Util.hs
--- a/test/Test/HsLua/Util.hs
+++ b/test/Test/HsLua/Util.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -32,7 +32,6 @@
   ) where
 
 import Data.ByteString (ByteString)
-import Data.Monoid ((<>))
 import Foreign.Lua ( Lua, run, runEither, loadstring, call, multret)
 import Test.Tasty (TestTree)
 import Test.Tasty.HUnit (Assertion, assertBool, assertFailure, testCase, (@?=))
diff --git a/test/test-hslua.hs b/test/test-hslua.hs
--- a/test/test-hslua.hs
+++ b/test/test-hslua.hs
@@ -1,5 +1,5 @@
 {-
-Copyright © 2017-2019 Albert Krewinkel
+Copyright © 2017-2020 Albert Krewinkel
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal