[amibroker] afl coding problem - buy signal when 2 conditions - one and then the other

[greenhorn1983]

hi everyone, 
how can I programe buy signal so it would be generated if: two
conditions occur, 
one and then the second one within specified time - precisesly within
1-9 bars after (signal shall not be generated if conditions occured at
the same time, as well as when the second condition occured earlier)
cheers,
greenhorn1983