Documentation

Sets a warning function. This is a simplified version of lua_setwarnf. The function at the top of the stack is set as the "warning hook", i.e., it is called with the concatenated warning components as the single argument.

The hook function is popped of the stack.

The control messages @on and @off are still supported; as with the default warning function, these commands can switch error reporting to stderr on and off. The given Haskell function will be called in either case, even when the error is not written to stderr.