/// Processes a Lua script.
///
/// This is a replacement for luaL_dostring but with proper error reporting
/// and stack control.
///
/// \param s The Lua state.
/// \param str The string to process.
/// \param nresults The number of results to expect; -1 for any.
///
/// \return The number of results left on the stack.
///
/// \throw error If there is a problem processing the string.
unsigned int
lutok::do_string(state& s, const std::string& str, const int nresults)
{
assert(nresults >= -1);
const int height = s.get_top();
stack_cleaner cleaner(s);
try {
s.load_string(str);
s.pcall(0, nresults == -1 ? LUA_MULTRET : nresults, 0);
} catch (const lutok::api_error& e) {
throw lutok::error("Failed to process Lua string '" + str + "': " +
e.what());
}
cleaner.forget();
const int actual_results = s.get_top() - height;
assert(nresults == -1 || actual_results == nresults);
assert(actual_results >= 0);
return static_cast< unsigned int >(actual_results);
}
