The overview is useful -- thanks. I see Allegro now does full TCO. Either that wasn't true when I was using it (a dozen years ago) or we just didn't have the

The overview is useful -- thanks. I see Allegro now does full TCO. Either that wasn't true when I was using it (a dozen years ago) or we just didn't have the right optimize switch settings to turn it on. In any case, I thought that the strategy of doing TCO only on local calls was pretty good -- it let me write loops tail-recursively with LABELS, but didn't significantly impact debugging because only local call frames got deleted. I'm well aware that the LispMs did not do TCO -- I owned several (starting with a CADR) and still have an XL1200 rusting in my closet :-)