undefined entries

[Graeme Forbes]

Rick:

How about this?

You have n properties P1 to Pn making for n rows in the table. As I 
understand it, the number of entires on each row can vary. Define a 
nonsense string that couldn't be the value of any of the properties. 
Put it in wherever needed so that all the rows have the same number 
of entries as the longest row(s). Now generate an uber-list of lists, 
where each member list contains exactly one value from each row. Then 
define a contraction routine that erases the nonsense string wherever 
it occurs in this list of lists. You now have a list of lists of 
variable length, and provided you didn't omit any "walk" down the 
table, all possible combinations of values for P1...Pn should be 
there.

Any good?

Graeme