Function invoke

include/covscript/core/core.hpp:462–475

// Invoke
	template <typename... ArgsT>
	static var invoke(const var &func, ArgsT &&..._args)
	{
		if (func.is_type_of<callable>()) {
			vector args{std::forward<ArgsT>(_args)...};
			return func.const_val<callable>().call(args);
		}
		else if (func.is_type_of<object_method>()) {
			const auto &om = func.const_val<object_method>();
			vector args{om.object, std::forward<ArgsT>(_args)...};
			return om.callable.const_val<callable>().call(args);
		}
		else
			throw runtime_error("Invoke non-callable object.");
	}

// Type and struct
	struct pointer final {