From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: gnuist006@gmail.com Newsgroups: gmane.emacs.help Subject: Re: The fundamental concept of continuations Date: Tue, 09 Oct 2007 06:33:24 -0000 Organization: http://groups.google.com Message-ID: <1191911604.169846.244430__15638.5708753534$1191912713$gmane$org@r29g2000hsg.googlegroups.com> References: <1191906949.179197.217470@57g2000hsv.googlegroups.com> <470b1aa6$0$79886$742ec2ed@news.sonic.net> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Trace: sea.gmane.org 1191912708 25531 80.91.229.12 (9 Oct 2007 06:51:48 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Tue, 9 Oct 2007 06:51:48 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Tue Oct 09 08:51:46 2007 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1If8wS-000513-5U for geh-help-gnu-emacs@m.gmane.org; Tue, 09 Oct 2007 08:51:44 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1If8wM-0002GM-QP for geh-help-gnu-emacs@m.gmane.org; Tue, 09 Oct 2007 02:51:38 -0400 Original-Path: shelby.stanford.edu!newsfeed.stanford.edu!postnews.google.com!r29g2000hsg.googlegroups.com!not-for-mail Original-Newsgroups: comp.lang.scheme, comp.lang.lisp, comp.lang.functional, gnu.emacs.help, comp.lang.python Original-Lines: 50 Original-NNTP-Posting-Host: 75.31.69.15 Original-X-Trace: posting.google.com 1191911604 32169 127.0.0.1 (9 Oct 2007 06:33:24 GMT) Original-X-Complaints-To: groups-abuse@google.com Original-NNTP-Posting-Date: Tue, 9 Oct 2007 06:33:24 +0000 (UTC) In-Reply-To: <470b1aa6$0$79886$742ec2ed@news.sonic.net> User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: r29g2000hsg.googlegroups.com; posting-host=75.31.69.15; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0 Original-Xref: shelby.stanford.edu comp.lang.scheme:74379 comp.lang.lisp:230759 comp.lang.functional:62586 gnu.emacs.help:152739 comp.lang.python:515500 X-Mailman-Approved-At: Tue, 09 Oct 2007 02:47:29 -0400 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:48245 Archived-At: On Oct 8, 11:07 pm, Bakul Shah wrote: > gnuist...@gmail.com wrote: > > > Again I am depressed to encounter a fundamentally new concept that I > > was all along unheard of. > > The concept is 37 years old. Wadsworth in his "Continuation > Revisited" paper says he & Strachey were struggling with > extending the technique of denotational semantics to describe > jumps and not finding a satisfactory answer. Then, in his > words: > > in October 1970 Strachey showed me a paper "Proving > algorithms by tail functions" by Mazurkiewicz [2] which he > had obtained from an IFIP WG2.2 meeting. Just the phrase > "tail functions" in the title was enough -- given the > experience of our earlier struggles -- for the ideas to > click into place! The (meaning of the) "rest of the program" > was needed as an argument to the semantic functions -- just > so those constructs that did not use it, like jumps, could > throw it anyway. The term "continuation" was coined as > capturing the essence of this extra argument (though I > often wished to have a shorter word!) and the rest, as they > say, is history. > > > Its not even in paul graham's book where i > > learnt part of Lisp. Its in Marc Feeley's video. > > > > Can anyone explain: > > > > (1) its origin > > (2) its syntax and semantics in emacs lisp, common lisp, scheme > > (3) Is it present in python and java ? > > (4) Its implementation in assembly. for example in the manner that > > pointer fundamentally arises from indirect addressing and nothing new. > > So how do you juggle PC to do it. > > (5) how does it compare to and superior to a function or subroutine > > call. how does it differ. > > > > Thanks a lot. > > > > (6) any good readable references that explain it lucidly ? > > You might like this one: > > http://www.intertwingly.net/blog/2005/04/13/Continuations-for-Curmudg... thanks for the link but can you plz upload the paper so we can also get it.