I have been trying to create what I thought should be simple codes for my use. But no matter what I try none work. So I must be getting something fundamental wrong.
EDIT on 1): after trying umpteen permutations of pattern, extension and coding in the post, I chanced on one that worked. Still am clueless about the principles.
on 2) I tried your suggestion but no success. It seems to me that the only bbcodes that I have been able to add are those with just one variable. Everything else just doesn't get interpreted. I have read the various posts around here but they didn't help. Is there any other information on how this interpretation works that could help me understand?