4 Sep
2007
4 Sep
'07
8:21 p.m.
On Sep 4, 2007, at 5:17 AM, Helmut Eller wrote:
- Tobias C. Rittweiler [2007-09-03 19:32+0200] writes:
Just a guess, but what I could imagine that `parse-first-valid-form-spec' in swank-arglist.lisp could possibly be the culprit, as it uses the "mapping on several lists, one being circular" trick:
(mapcar #'+ '(1 2 3 4) '#1=(10 . #1#))
I'd expect this one to return (11 12 13 14), but closely rereading the CLHS entry for the mapping functions, reveals that those are actually only defined for /proper lists/.
Never heard of this trick.
I think it's fair to consider it archaic, but it was once well known in Maclisp and early Lisp Machine Lisp. IIRC, the latter even had a builtin function `circular-list' to simplify the construction of such lists.
-- Scott