[imapfilter-devel] subsearch of results

[Josef]

Hello there,
    I'm a bit lost with LUA. I'm trying to do this:
results = ( account1.INBOX:is_unseen() *
            account1.INBOX:match_header('X-Spam-Flag: YES') )

But as the inbox contains >10000 messages, this would be too slow. So I 
would like to search for spam flag only those messages, that are new, 
not doing the search again. I tought of this:
results = account1.INBOX:is_unseen()
newresults = results:match_header('X-Spam-Flag: YES')

But the imapfilter keeps on returning this error:
imapfilter: pepus at p-h-a.cz:9: attempt to call method 'match_header' (a 
nil value)

Am I doing anyting wrong? Or is there a way to achieve this?

Thank you a lot,
    Josef