Hi, I'm trying to write a grammar for a scripting language, and to do this I'm building an AST of each expression. I have this working fine, for the most part, but I've run into a problem -- I can't seem to figure out how to put right-to-left associative operators into the tree properly. I had this as a guess, but I'm really not sure: r = value | value >> root_node_d[ch_p('=')] >> r; _____________________________________________________________ <a href="http://www.gamedev.net">GameDev.net Email Service</a> - "Plenty of 1's and 0's" _____________________________________________________________ Select your own custom email address for FREE! Get you@yourchoice.com, No Ads, 6MB, IMAP, POP, SMTP & more! http://www.everyone.net/selectmail?campaign=tag