can I do this without script?

["Steve Dugas" <sjdugas@xxxx>]

Hello All,
 
I am stuck on what was supposed to be some very simple code, 
and grew into a problem.  I wonder if someone would be kind 
enough to give me some advise. Details are below, but to make a long story 
short:
 
Here is what I am trying to code (simple moving average 
reversal - buy when average turns up):
 
buy = today's MA  >  yesterday's MA
AND
yesterday's MA  <  MA of most recent day 
before yesterday whose  MA was not equal to yesterday's
 
Here is what I have so far:
 
buy = ma(close,30) > ref(ma(close,30),-1)
AND
ref(ma(close,30),-1) < ? (this is the tough 
part)
 
Tomasz says that 90% (or whatever) of things can be coded 
without using scripts. Can this one be done in AFL? It looks like I need to 
iterate the database, right?
 
OK, here comes the whole sad story for anyone who is 
interested:
 
I originally thought this would be very simple to code,and I 
coded it as follows:
 

buy = ma(close,30) > ref(ma(close,30),-1)
AND
ref(ma(close,30),-1) <  
ref(ma(close,30),-2)
 
After I ran this, and was looking at the resulting trade arrows on the 
chart, it was obvious that I was missing some trades (and some BIG price 
moves).  I did a quick exploration to debug it, which revealed that (for 
many stocks, over a long period) there are MANY instances where the moving 
average does not change for 2, 3, even 10 or more days in a row. It 
remains the same right out to 9 decimal places! One reason for this appears 
to be that for some stocks, even though they trade frequently enough now, they 
would sometimes go for days without a trade in their early days. There may be 
other reasons too, I didnt follow up on all of them. So this brings me to my 
current situation - my original simple code only works correctly if the MA 
changes every day, which sometimes it doesnt. In order to make this work 
properly, I need to look back, day-by-day, starting with the 
day-before-yesterday, until I come to a day whose moving average is different 
than yesterday's, and then use that days MA in my formula. Any advise is greatly 
appreciated. Thanks very much!
 
Steve