Structured editing on the Lisp Machine

I'm curious if they had something of that sort for Zmacs, like we have Paredit for Emacs today.

Trying to search for it on google pointed me to this paper http://portal.acm.org/citation.cfm?doid=356744.356754 written by rms, but I don't have an ACM subscription, so I can't get a copy of that paper, nor do I know how relevant it is to this topic.

s/CFID=[0-9]+&CFTOKEN=[0-9]+/CFID=15151515&CFTOKEN=6184618/