Robert,
Your recommendation will work fine for many of the simpler Buy and Sell Rules.
Buy is not workable for more complex Rules and even some simple ones. A few examples:
Buy Rules;
MktCap > 50 & MktCap < 500
SecWeight <15
MaxCorrel(60,1) < 0.5
Sell Rules;
NoDays > 20 and GainPct < BenchPct
PctFromHi < -20
Pr4W%Chg / 20 <.1 & NoDays > 30
You could reverse the > and < signs on some of them and make it work, but that is not simpler, and it is easy to over look when changing it back.
Denny