thanks for the insights. What I'm leaning towards at this point is to have a tabular entry form with different simple actions that can be performed on different fields. The individual actions would be grouped to make a rule. (The rules I need to create bundle specific groups of items together, each at various discounts or set prices)

So, when the user chooses to enter a new rule, I start adding rows to my rules table with the same group_id value. The user would provide values for field, comparison/action, and value. The action could be a comparison to establish whether the rule may be applied, and an assignment, to set different fields to a certain value.

I guess my question was more about how to best achieve the above syntactically, or if I should use a slightly different entry structure.

I'm assuming that the people entering the rules are fairly smart (dangerous, I know) and also have a strong knowledge of the conditions they want their rules to work under.

Further feedback on this would be, of course, very welcome.

Thanks all you Monks,

Andy