From ... From: Erik Naggum Subject: Re: Performance tuning Date: 2000/12/07 Message-ID: <3185215881931249@naggum.net>#1/1 X-Deja-AN: 702332246 References: <3184953833736032@naggum.net> <3A2C7C38.4F68956A@fisec.com> <3185025504930095@naggum.net> <90jju3$44s$1@reader1.fr.uu.net> <3185044115971786@naggum.net> <3A2E1240.C8911FE@anglia.ac.uk> <3185194562763651@naggum.net> mail-copies-to: never Content-Type: text/plain; charset=us-ascii X-Complaints-To: newsmaster@eunet.no X-Trace: oslo-nntp.eunet.no 976227422 27486 195.0.192.66 (7 Dec 2000 22:17:02 GMT) Organization: Naggum Software; vox: +47 800 35477; gsm: +47 93 256 360; fax: +47 93 270 868; http://naggum.no; http://naggum.net User-Agent: Gnus/5.0803 (Gnus v5.8.3) Emacs/20.7 Mime-Version: 1.0 NNTP-Posting-Date: 7 Dec 2000 22:17:02 GMT Newsgroups: comp.lang.lisp * Tim Bradshaw | Surely the semantic change is somnething like: | | (defun foo (x) | (declare (type integer x)) | (let ((y x)) | ;; if X is a bignum then Y is a pointer to X, if X is a fixnum then | ;; Y is a copy of X (probably?) | (bar y) | ;; right now this is true. if DPB modifies bignums it will be | ;; true only if y was odd. | (= x y))) | | (defun bar (y) | (declare (type integer y)) | (dpb 1 (byte 1 0) y)) Well, I _had_ hoped to see semething a tad less contrived, as this is bad style on so many counts that I'm likely to believe nobody has done anything like this that would cause a _change_ in observable behavior. To find a change in semantics, you would at least have to find something that people do today with dpb (or setf of ldb). But at worst, we could define a destructive version of dpb, which would be pretty easy to write even today. #:Erik -- "When you are having a bad day and it seems like everybody is trying to piss you off, remember that it takes 42 muscles to produce a frown, but only 4 muscles to work the trigger of a good sniper rifle." -- Unknown