With this patch lua nil values are mapped to CQL null values instead
of producing an error.
Fixes#5667
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
This add a wrapper around the lua interpreter so that function
executions are interruptible and return futures.
With this patch it is possible to write and use simple UDFs that take
and return integer values.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>