No, it was a mistake by me: Anarki works similarly to ArcN in this case. Sorry for muddying the waters. ^^
The problem appears to be that the current '= was meant for use with the older ssyntax, which supports only : for composition. I'll take a better look maybe later, I'm just home from work, cooling off (very hot in the philippines right now)
The "invert" thing is really confusing, I didn't add docstrings to all the '= related stuff because of that. Me, I say refactor '=. LOL
Edit: Fixed on the git.
(def metafn (x)
(set x (ssyntax x))
(and (acons x) (in (car x) 'compose 'complement)))