From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 23 Aug 2009 22:59:00 +0300 From: Aharon Robbins In-reply-to: <3aaafc130908211810u3afbd969ne259a57162d07325@mail.gmail.com> To: jrm8005@gmail.com Message-id: <200908231959.n7NJx0e4004027@skeeve.com> Content-transfer-encoding: 7BIT References: Cc: 9fans@9fans.net Subject: Re: [9fans] Recursive structural expressions? Topicbox-Message-UUID: 520c6f90-ead5-11e9-9d60-3106f5b1d025 I have a file dated October 30 1987 which is the source for a qed clone written at U of Toronto. A quick glance at the man page seems to indicate that it doesn't have recursive regular expressions. I'm not sure who I got it from - possibly Henry Spencer. Anyone know anymore about it? I can put it up where people can get to it if there's interest. Thanks, Arnold In article <3aaafc130908211810u3afbd969ne259a57162d07325@mail.gmail.com> you write: >On Thu, Aug 20, 2009 at 9:14 PM, Charles Forsyth wrote: >> qed allowed naming of regular expressions using `e' and their >recursive invocation >> using \E, with results suggested earlier. >> >> http://cm.bell-labs.com/cm/cs/who/dmr/qedman.html >> http://cm.bell-labs.com/cm/cs/who/dmr/qedman.pdf >> >> ``It should be noted that the ability to define regular expressions >recursively makes the term "regular expression" a misnomer: it is not >hard to see that expressions can be constructed to match exactly the >members of any given context-free language.'' >> >> > >I guess I missed this when I last read that paper. Do you know how qed >dealt with infinite recursion or ambiguous CF expressions? > -- Aharon (Arnold) Robbins arnold AT skeeve DOT com P.O. Box 354 Home Phone: +972 8 979-0381 Nof Ayalon Cell Phone: +972 50 729-7545 D.N. Shimshon 99785 ISRAEL