In C it is possible to have methods without arguments (UBUS_METHOD_NOARG).
Enable support for the same calls in Lua too.
This commit also fixes segfault which can be caused by passing non-table type
where table is expected. The lua_gettablelen() function is called after we have
made sure we are dealing with a table in the first place.
Signed-off-by: Luka Perkov <luka@openwrt.org>
It mostly mimick the style of the existing code.
With it and the ubox Lua bindings, you can now send ubus events
through Lua or listen for events (you can register for multiple events
at the same time).
Signed-off-by: Jeff Remy <jeff.remy@gmail.com>
