1. AND, OR, NOT logic rules
I think forexer is right. If we mark opening filters as AND or OR we can set several AND conditions that all have to be true an several single OR conditions. We need some kind of parenthesis to be able to group several relative filters that all have to be true. As I see the groups he offers serves as parenthesis.
Probably we can mark the entry filters as:
1. Main entry logic; and
2. Alternative entry logic.
An entry to be executed either when all the "main logic conditions" or all the "alternative logic conditions" are true.
We actually don't need NOT logic. It's because most of the indicators have "right" and "opposite" logic rules.
e.g. If you want to enter long when MA13 rises and MA21 doesn't rise, you can set:
1. MA13 rises; and
2. MA21 falls.
2. long, short indicators
It's easy to make the indicators to work for "long and short", "long only" or "short only", but I cannot see real benefits of this. That will give someone the possibility for building "asymmetric" strategies with different rules for long and for short entry. I personally will not accept such strategy because of the curve fitting.
Lets say we have an uptrend during the testing period. An asymmetric strategy can allow an easier long entry than a short one. This will work only during the uptrend but not after the trend has finished.
Actually we can do this with a "symmetric" strategy like the current ones in FSB. It's enough to include a long therm MA (MA rises) or a MACD (MACD > 0) to trade explicitly in the trend direction.