Jan Vroonhof <vroonhof(a)math.ethz.ch&gt; writes: That type would have to be an lrecord. Draw your own conclusion. 21.0 does. The very first item under "Lisp and internal changes" in its NEWS entry. How does that cripple my XEmacs? It might cripple my system, but not XEmacs. The same way you could say that image support, variable width fonts, variable height lines and all that cruft "cripples" my XEmacs because of an "enormous memory overhead". I choose integer. There must be other ways of dealing with chars. We've lived with 8-bit and 19-bit (19! what a number!) chars for quite a while. Surely a scheme can be devised for them to be thirty bit. No "scheme" will buy you 31-bit integers except the current one, and bignums. And bignums are hard. I constructed the hypothetical question and stand by the hypothetical answer. I'm sure people *do* think that way. Or do you think they will buy an alpha or ultrasparc rather than compile --without-mule? In your dreams! Mule is the doom of us all, I can tell. Have you tried it? I have tried 600M buffers, and things worked reasonably fast -- i.e. slow as hell, but workable in case of emergency. I still don't understand your remark about O(n^2) operations, though.