Re: I must be going mad!

ms> As you saw, my Scheme implementation (Scheme 48) isn't willing This is publically available, right? (I'm to do a introductory presentation on Python at a LUG, contrasting Scheme, Elisp, and Python on this point seems like a useful thing to do.) ms> to do this---this is due to proper checking of read-only ms> status for heap objects. Ah, I see. Python gets this right. There's no "cons" type so implementation is hidden. Read-only and read-write sequences have different literal notations but the same read APIs. Notations defining places are the same for read and write so effectively there are no write notations except setf. Python also provides an alist-like literal notation for hashes, which have a subset of the sequence APIs (ie, APIs which imply order are missing, but notations for the common APIs are the same). That actually is quite reminiscent of the style you favor, it seems to me, but Python enforces it and provides some syntactic sugar. -- Institute of Policy and Planning Sciences http://turnbull.sk.tsukuba.ac.jp University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN My nostalgia for Icon makes me forget about any of the bad things. I don't have much nostalgia for Perl, so its faults I remember. Scott Gilbert c.l.py