Lua.Primary

Haskell bindings to Lua C API functions.

The exposed functions correspond closely to the respective C Lua API functions. However, C API functions which can throw Lua errors are not exported directly, as any errors would crash the program. Non-error throwing hslua_ versions are provided instead. The hslua ersatz functions have worse performance than the original.

Some of the Lua functions may, directly or indirectly, call a Haskell function, and trigger garbage collection, rescheduling etc. These functions are always imported safely (i.e., with the safe keyword).

However, all function can trigger garbage collection. If that can lead to problems, then the package should be configured without flag allow-unsafe-gc.

Documentation

lua_absindex

Arguments

:: State

-> StackIndex

idx

-> IO StackIndex

Converts the acceptable index idx into an equivalent absolute index (that is, one that does not depend on the stack top).

https://www.lua.org/manual/5.3/manual.html#lua_absindex

lua_checkstack

Arguments

:: State

-> CInt

n

-> IO LuaBool

Ensures that the stack has space for at least n extra slots (that is, that you can safely push up to n values into it). It returns false if it cannot fulfill the request, either because it would cause the stack to be larger than a fixed maximum size (typically at least several thousand elements) or because it cannot allocate memory for the extra space. This function never shrinks the stack; if the stack already has space for the extra slots, it is left unchanged.

https://www.lua.org/manual/5.3/manual.html#lua_checkstack

lua_close :: State -> IO ()

Destroys all objects in the given Lua state (calling the corresponding garbage-collection metamethods, if any) and frees all dynamic memory used by this state. In several platforms, you may not need to call this function, because all resources are naturally released when the host program ends. On the other hand, long-running programs that create multiple states, such as daemons or web servers, will probably need to close states as soon as they are not needed.

https://www.lua.org/manual/5.3/manual.html#lua_close

lua_concat

Arguments

:: State

-> CInt

n

-> IO ()

Warning: This is an unsafe function, it will cause a program crash ifa metamethod throws an error.Consider using hslua_concat instead.

Concatenates the n values at the top of the stack, pops them, and leaves the result at the top. If n is 1, the result is the single value on the stack (that is, the function does nothing); if n is 0, the result is the empty string. Concatenation is performed following the usual semantics of Lua (see §3.4.6 of the Lua manual).

WARNING: lua_concat is unsafe in Haskell: This function will cause an unrecoverable crash an error if any of the concatenated values causes an error when executing a metamethod. Consider using the hslua_concat ersatz function instead.

lua_copy

Arguments

:: State

-> StackIndex

fromidx

-> StackIndex

toidx

-> IO ()

Copies the element at index fromidx into the valid index toidx, replacing the value at that position. Values at other positions are not affected.

https://www.lua.org/manual/5.3/manual.html#lua_copy

lua_createtable

Arguments

:: State

-> CInt

narr

-> CInt

nrec

-> IO ()

Creates a new empty table and pushes it onto the stack. Parameter narr is a hint for how many elements the table will have as a sequence; parameter nrec is a hint for how many other elements the table will have. Lua may use these hints to preallocate memory for the new table. This preallocation is useful for performance when you know in advance how many elements the table will have. Otherwise you can use the function lua_newtable.

https://www.lua.org/manual/5.3/manual.html#lua_createtable.

lua_gc

Arguments

:: State

-> GCCode

what

-> CInt

data

-> IO CInt

Controls the garbage collector.

See the Lua docs at https://www.lua.org/manual/5.3/manual.html#lua_gc.

lua_getglobal

Arguments

:: State

-> CString

name

-> IO TypeCode

Warning: This is an unsafe function, errors will lead to a program crash;consider using hslua_getglobal instead.

Pushes onto the stack the value of the global name. Returns the type of that value.

WARNING: lua_getglobal is unsafe in Haskell: if the call to a metamethod triggers an error, then that error cannot be handled and will lead to an unrecoverable program crash. Consider using the hslua_getglobal ersatz function instead. Likewise, the metamethod may not call a Haskell function unless the library was compiled without allow-unsafe-gc.

https://www.lua.org/manual/5.3/manual.html#lua_getglobal.

lua_getmetatable :: State -> StackIndex -> IO LuaBool

If the value at the given index has a metatable, the function pushes that metatable onto the stack and returns 1. Otherwise, the function returns 0 and pushes nothing on the stack.

https://www.lua.org/manual/5.3/manual.html#lua_getmetatable.

lua_gettable

Arguments

:: State

-> StackIndex

index

-> IO TypeCode

Warning: This is an unsafe function, errors will lead to a program crash;consider using hslua_gettable instead.

Pushes onto the stack the value t[k], where t is the value at the given index and k is the value at the top of the stack.

This function pops the key from the stack, pushing the resulting value in its place. As in Lua, this function may trigger a metamethod for the "index" event (see §2.4).

Returns the type of the pushed value.

WARNING: lua_gettable is unsafe in Haskell: if the call to a metamethod triggers an error, then that error cannot be handled and will lead to an unrecoverable program crash. Consider using the hslua_gettable ersatz function instead. Likewise, the metamethod may not call a Haskell function unless the library was compiled without allow-unsafe-gc.

https://www.lua.org/manual/5.3/manual.html#lua_gettable.

lua_gettop :: State -> IO StackIndex

Returns the index of the top element in the stack. Because indices start at 1, this result is equal to the number of elements in the stack (and so 0 means an empty stack).

https://www.lua.org/manual/5.3/manual.html#lua_gettop

lua_getuservalue :: State -> StackIndex -> IO TypeCode

Pushes onto the stack the Lua value associated with the full userdata at the given index.

Returns the type of the pushed value.

https://www.lua.org/manual/5.3/manual.html#lua_getuservalue

lua_insert :: State -> StackIndex -> IO ()

Moves the top element into the given valid index, shifting up the elements above this index to open space. This function cannot be called with a pseudo-index, because a pseudo-index is not an actual stack position.

https://www.lua.org/manual/5.3/manual.html#lua_insert

lua_isboolean :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a boolean, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isboolean

lua_iscfunction :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a C function, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_iscfunction

lua_isfunction :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a function (either C or Lua), and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isfunction

lua_isinteger :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is an integer (that is, the value is a number and is represented as an integer), and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isinteger

lua_islightuserdata :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a light userdata, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_islightuserdata

lua_isnil :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is nil, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isnil

lua_isnone :: State -> StackIndex -> IO LuaBool

Returns TRUE if the given index is not valid, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isnone

lua_isnoneornil :: State -> StackIndex -> IO LuaBool

Returns TRUE if the given index is not valid or if the value at the given index is nil, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isnoneornil

lua_isnumber :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a number or a string convertible to a number, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isnumber

lua_isstring :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a string or a number (which is always convertible to a string), and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isstring

lua_istable :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a table, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_istable

lua_isthread :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a thread, and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isthread

lua_isuserdata :: State -> StackIndex -> IO LuaBool

Returns TRUE if the value at the given index is a userdata (either full or light), and FALSE otherwise.

https://www.lua.org/manual/5.3/manual.html#lua_isuserdata

lua_load

Arguments

:: State

-> Reader

reader

-> Ptr ()

data

-> CString

chunkname

-> CString

mode

-> IO StatusCode

Loads a Lua chunk (without running it). If there are no errors, lua_load pushes the compiled chunk as a Lua function on top of the stack. Otherwise, it pushes an error message.

The return values of lua_load are:

• LUA_OK: no errors;
• LUA_ERRSYNTAX: syntax error during pre-compilation;
• LUA_ERRMEM: memory allocation error;
• LUA_ERRGCMM: error while running a __gc metamethod. (This error has no relation with the chunk being loaded. It is generated by the garbage collector.)

This function only loads a chunk; it does not run it.

lua_load automatically detects whether the chunk is text or binary, and loads it accordingly (see program luac).

The lua_load function uses a user-supplied reader function to read the chunk (see Reader). The data argument is an opaque value passed to the reader function.

The chunkname argument gives a name to the chunk, which is used for error messages and in debug information (see §4.9).

lua_load automatically detects whether the chunk is text or binary and loads it accordingly (see program luac). The string mode works as in function load, with the addition that a NULL value is equivalent to the string "bt".

lua_load uses the stack internally, so the reader function must always leave the stack unmodified when returning.

https://www.lua.org/manual/5.3/manual.html#lua_load.

lua_newthread :: State -> IO State

Creates a new thread, pushes it on the stack, and returns a State that represents this new thread. The new thread returned by this function shares with the original thread its global environment, but has an independent execution stack.

There is no explicit function to close or to destroy a thread. Threads are subject to garbage collection, like any Lua object.

https://www.lua.org/manual/5.3/manual.html#lua_newthread

lua_newuserdata :: State -> CSize -> IO (Ptr ())

This function allocates a new block of memory with the given size, pushes onto the stack a new full userdata with the block address, and returns this address. The host program can freely use this memory.

https://www.lua.org/manual/5.3/manual.html#lua_newuserdata.

lua_next

Arguments

:: State

-> StackIndex

index

-> IO LuaBool

Warning: This is an unsafe function, it will cause a program crash ifthe given key is neither nil nor present in the table.Consider using hslua_next instead.

Pops a key from the stack, and pushes a key–value pair from the table at the given index (the "next" pair after the given key). If there are no more elements in the table, then lua_next returns FALSE (and pushes nothing).

A typical traversal looks like this:

-- table is in the stack at index 't'
lua_pushnil l    -- first key
let loop = lua_next l t >>= \case
      FALSE -> return ()
      _ -> do
        lua_type l (-2) >>= lua_typename l >>= peekCString >>= putStrLn
        lua_type l (-1) >>= lua_typename l >>= peekCString >>= putStrLn
        -- removes 'value'; keeps 'key' for next iteration
        lua_pop l 1
        loop
loop

While traversing a table, do not call lua_tolstring directly on a key, unless you know that the key is actually a string. Recall that lua_tolstring may change the value at the given index; this confuses the next call to lua_next.

See function next for the caveats of modifying the table during its traversal.

WARNING: lua_next is unsafe in Haskell: This function will cause an unrecoverable crash an error if the given key is neither nil nor present in the table. Consider using the hslua_next ersatz function instead.

lua_pcall

Arguments

:: State

-> NumArgs

nargs

-> NumResults

nresults

-> StackIndex

msgh

-> IO StatusCode

Calls a function in protected mode.

To call a function you must use the following protocol: first, the function to be called is pushed onto the stack; then, the arguments to the function are pushed in direct order; that is, the first argument is pushed first. Finally you call lua_pcall; nargs is the number of arguments that you pushed onto the stack. All arguments and the function value are popped from the stack when the function is called. The function results are pushed onto the stack when the function returns. The number of results is adjusted to nresults, unless nresults is LUA_MULTRET. In this case, all results from the function are pushed. Lua takes care that the returned values fit into the stack space. The function results are pushed onto the stack in direct order (the first result is pushed first), so that after the call the last result is on the top of the stack.

If there is any error, lua_pcall catches it, pushes a single value on the stack (the error message), and returns the error code. lua_pcall always removes the function and its arguments from the stack.

If msgh is 0, then the error object returned on the stack is exactly the original error object. Otherwise, msgh is the location of a message handler. (This index cannot be a pseudo-index.) In case of runtime errors, this function will be called with the error object and its return value will be the object returned on the stack by lua_pcall.

Typically, the message handler is used to add more debug information to the error object, such as a stack traceback. Such information cannot be gathered after the return of lua_pcall, since by then the stack has unwound.

https://www.lua.org/manual/5.3/manual.html#lua_pcall.

lua_pop

Arguments

:: State

-> CInt

n

-> IO ()

Pops n elements from the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pop

lua_pushboolean :: State -> LuaBool -> IO ()

Pushes a boolean value with the given value onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushboolean.

lua_pushcclosure

Arguments

:: State

-> CFunction

fn

-> NumArgs

n

-> IO ()

Pushes a new C closure onto the stack.

When a C function is created, it is possible to associate some values with it, thus creating a C closure (see §3.4); these values are then accessible to the function whenever it is called. To associate values with a C function, first these values should be pushed onto the stack (when there are multiple values, the first value is pushed first). Then lua_pushcclosure is called to create and push the C function onto the stack, with the argument n telling how many values should be associated with the function. lua_pushcclosure also pops these values from the stack.

The maximum value for n is 255.

https://www.lua.org/manual/5.3/manual.html#lua_pushcclosure.

lua_pushglobaltable :: State -> IO ()

Pushes the global environment onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushglobaltable

lua_pushinteger :: State -> Integer -> IO ()

Pushes an integer with with the given value onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushinteger.

lua_pushlightuserdata :: State -> Ptr a -> IO ()

Pushes a light userdata onto the stack.

Userdata represent C values in Lua. A light userdata represents a pointer, a Ptr () (i.e., void* in C lingo). It is a value (like a number): you do not create it, it has no individual metatable, and it is not collected (as it was never created). A light userdata is equal to "any" light userdata with the same C address.

https://www.lua.org/manual/5.3/manual.html#lua_pushlightuserdata.

lua_pushlstring

Arguments

:: State

-> Ptr CChar

s

-> CSize

len

-> IO ()

Pushes the string pointed to by s with size len onto the stack. Lua makes (or reuses) an internal copy of the given string, so the memory at s can be freed or reused immediately after the function returns. The string can contain any binary data, including embedded zeros.

Returns a pointer to the internal copy of the string.

https://www.lua.org/manual/5.3/manual.html#lua_pushlstring.

lua_pushnil :: State -> IO ()

Pushes a nil value onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushnil.

lua_pushnumber :: State -> Number -> IO ()

Pushes a float with the given value onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushnumber.

lua_pushstring

Arguments

:: State

-> CString

s

-> IO CString

Pushes the zero-terminated string pointed to by s onto the stack. Lua makes (or reuses) an internal copy of the given string, so the memory at s can be freed or reused immediately after the function returns.

Returns a pointer to the internal copy of the string.

If s is NULL, pushes nil and returns NULL.

lua_pushthread :: State -> IO CInt

Pushes the current thread onto the stack. Returns 1 iff this thread is the main thread of its state.

https://www.lua.org/manual/5.3/manual.html#lua_pushthread.

lua_pushvalue :: State -> StackIndex -> IO ()

Pushes a copy of the element at the given index onto the stack.

https://www.lua.org/manual/5.3/manual.html#lua_pushvalue

lua_rawequal

Arguments

:: State

-> StackIndex

idx1

-> StackIndex

idx2

-> IO LuaBool

Returns True if the two values in indices idx1 and idx2 are primitively equal (that is, without calling the __eq metamethod). Otherwise returns False. Also returns False if any of the indices are not valid.

https://www.lua.org/manual/5.3/manual.html#lua_rawequal

lua_rawget :: State -> StackIndex -> IO ()

Similar to lua_gettable, but does a raw access (i.e., without metamethods).

https://www.lua.org/manual/5.3/manual.html#lua_rawget.

lua_rawgeti

Arguments

:: State

-> StackIndex

-> Integer

n

-> IO ()

Pushes onto the stack the value t[n], where t is the table at the given index. The access is raw, that is, it does not invoke the __index metamethod.

https://www.lua.org/manual/5.3/manual.html#lua_rawgeti.

lua_rawlen :: State -> StackIndex -> IO CSize

Returns the raw "length" of the value at the given index: for strings, this is the string length; for tables, this is the result of the length operator (#) with no metamethods; for userdata, this is the size of the block of memory allocated for the userdata; for other values, it is 0.

https://www.lua.org/manual/5.3/manual.html#lua_rawlen.

lua_rawset :: State -> StackIndex -> IO ()

Similar to lua_settable, but does a raw assignment (i.e., without metamethods).

https://www.lua.org/manual/5.3/manual.html#lua_rawset.

lua_rawseti :: State -> StackIndex -> Integer -> IO ()

Does the equivalent of t[i] = v, where t is the table at the given index and v is the value at the top of the stack.

This function pops the value from the stack. The assignment is raw, that is, it does not invoke the __newindex metamethod.

https://www.lua.org/manual/5.3/manual.html#lua_rawseti.

lua_remove :: State -> StackIndex -> IO ()

Removes the element at the given valid index, shifting down the elements above this index to fill the gap. This function cannot be called with a pseudo-index, because a pseudo-index is not an actual stack position.

https://www.lua.org/manual/5.3/manual.html#lua_remove

lua_replace :: State -> StackIndex -> IO ()

Moves the top element into the given valid index without shifting any element (therefore replacing the value at that given index), and then pops the top element.

https://www.lua.org/manual/5.3/manual.html#lua_replace

lua_setglobal

Arguments

:: State

-> CString

name

-> IO ()

Warning: This is an unsafe function, errors will lead to a program crash;consider using hslua_getglobal instead.

Pops a value from the stack and sets it as the new value of global name.

WARNING: lua_setglobal is unsafe in Haskell: if the call to a metamethod triggers an error, then that error cannot be handled and will lead to an unrecoverable program crash. Consider using the hslua_setglobal ersatz function instead. Likewise, the global metamethod may not call a Haskell function unless the library was compiled without allow-unsafe-gc.

https://www.lua.org/manual/5.3/manual.html#lua_setglobal.

lua_setmetatable :: State -> StackIndex -> IO ()

Pops a table from the stack and sets it as the new metatable for the value at the given index.

https://www.lua.org/manual/5.3/manual.html#lua_setmetatable.

lua_settable

Arguments

:: State

-> StackIndex

index

-> IO ()

Warning: This is an unsafe function, errors will lead to a program crash;consider using hslua_settable instead.

Does the equivalent to t[k] = v, where t is the value at the given index, v is the value at the top of the stack, and k is the value just below the top.

This function pops both the key and the value from the stack. As in Lua, this function may trigger a metamethod for the "newindex" event (see §2.4).

WARNING: lua_settable is unsafe in Haskell: if the call to a metamethod triggers an error, then that error cannot be handled and will lead to an unrecoverable program crash. Consider using the hslua_settable ersatz function instead. Likewise, the metamethod may not call a Haskell function unless the library was compiled without allow-unsafe-gc.

https://www.lua.org/manual/5.3/manual.html#lua_settable

lua_settop

Arguments

:: State

-> StackIndex

index

-> IO ()

Accepts any index, or 0, and sets the stack top to this index. If the new top is larger than the old one, then the new elements are filled with *nil*. If index is 0, then all stack elements are removed.

https://www.lua.org/manual/5.3/manual.html#lua_settop

lua_setuservalue :: State -> StackIndex -> IO ()

Pops a value from the stack and sets it as the new value associated to the full userdata at the given index.

https://www.lua.org/manual/5.3/manual.html#lua_setuservalue

lua_status :: State -> IO StatusCode

Returns the status of this Lua thread.

The status can be LUA_OK for a normal thread, an error value if the thread finished the execution of a lua_resume with an error, or LUA_YIELD if the thread is suspended.

You can only call functions in threads with status LUA_OK. You can resume threads with status LUA_OK (to start a new coroutine) or LUA_YIELD (to resume a coroutine).

https://www.lua.org/manual/5.3/manual.html#lua_status.

lua_toboolean :: State -> StackIndex -> IO LuaBool

Converts the Lua value at the given index to a haskell boolean value. Like all tests in Lua, toboolean returns True for any Lua value different from *false* and *nil*; otherwise it returns False. (If you want to accept only actual boolean values, use lua_isboolean to test the value's type.)

https://www.lua.org/manual/5.3/manual.html#lua_toboolean

lua_tocfunction :: State -> StackIndex -> IO CFunction

Converts a value at the given index to a C function. That value must be a C function; otherwise, returns Nothing.

https://www.lua.org/manual/5.3/manual.html#lua_tocfunction

lua_tointegerx

Arguments

:: State

-> StackIndex

index

-> Ptr LuaBool

isnum

-> IO Integer

Converts the Lua value at the given acceptable index to the signed integral type Integer. The Lua value must be an integer, a number, or a string convertible to an integer (see §3.4.3 of the Lua 5.3 Reference Manual); otherwise, lua_tointegerx returns 0.

If the number is not an integer, it is truncated in some non-specified way.

If isnum is not NULL, its referent is assigned a boolean value that indicates whether the operation succeeded.

https://www.lua.org/manual/5.3/manual.html#lua_tointegerx

lua_tolstring

Arguments

:: State

-> StackIndex

index

-> Ptr CSize

len

-> IO (Ptr CChar)

Converts the Lua value at the given index to a C string. If len is not NULL, it sets the referent with the string length. The Lua value must be a string or a number; otherwise, the function returns NULL. If the value is a number, then lua_tolstring also changes the actual value in the stack to a string. (This change confuses lua_next when lua_tolstring is applied to keys during a table traversal.)

lua_tolstring returns a pointer to a string inside the Lua state. This string always has a zero ('0') after its last character (as in C), but can contain other zeros in its body.

Because Lua has garbage collection, there is no guarantee that the pointer returned by lua_tolstring will be valid after the corresponding Lua value is removed from the stack.

https://www.lua.org/manual/5.3/manual.html#lua_tolstring

lua_tonumberx

Arguments

:: State

-> StackIndex

index

-> Ptr LuaBool

isnum

-> IO Number

Converts the Lua value at the given index to the C type lua_Number (see lua_Number). The Lua value must be a number or a string convertible to a number (see §3.4.3); otherwise, lua_tonumberx returns 0.

If isnum is not NULL, its referent is assigned a boolean value that indicates whether the operation succeeded.

https://www.lua.org/manual/5.3/manual.html#lua_tonumberx

lua_topointer :: State -> StackIndex -> IO (Ptr ())

Converts the value at the given index to a generic C pointer (void*). The value can be a userdata, a table, a thread, or a function; otherwise, lua_topointer returns nullPtr. Different objects will give different pointers. There is no way to convert the pointer back to its original value.

Typically this function is used only for hashing and debug information.

https://www.lua.org/manual/5.3/manual.html#lua_topointer

lua_tothread :: State -> StackIndex -> IO State

Converts the value at the given index to a Lua thread (represented as State). This value must be a thread; otherwise, the function returns nullPtr.

https://www.lua.org/manual/5.3/manual.html#lua_tothread

lua_touserdata :: State -> StackIndex -> IO (Ptr a)

If the value at the given index is a full userdata, returns its block address. If the value is a light userdata, returns its pointer. Otherwise, returns nullPtr.

https://www.lua.org/manual/5.3/manual.html#lua_touserdata

lua_type :: State -> StackIndex -> IO TypeCode

Returns the type of the value in the given valid index, or LUA_TNONE for a non-valid (but acceptable) index.

https://www.lua.org/manual/5.3/manual.html#lua_type

lua_typename

Arguments

:: State

-> TypeCode

tp

-> IO CString

Returns the name of the type encoded by the value tp, which must be one the values returned by lua_type.

https://www.lua.org/manual/5.3/manual.html#lua_typename

module Lua.Ersatz.Functions

module Lua.Ersatz.Auxiliary