Return-Path: Delivery-Date: Received: from ted.cs.uidaho.edu by swan.cl.cam.ac.uk with SMTP (PP-6.2); Wed, 23 Dec 1992 13:23:32 +0000 Received: by ted.cs.uidaho.edu (16.6/1.34) id AA10139; Wed, 23 Dec 92 05:11:03 -0800 Sender: info-hol-request@edu.uidaho.cs.ted Errors-To: info-hol-request@edu.uidaho.cs.ted Precedence: bulk Received: from scylla.oracorp.com by ted.cs.uidaho.edu (16.6/1.34) id AA10134; Wed, 23 Dec 92 05:10:56 -0800 Received: from sparta.oracorp.com by oracorp.com (4.1/2.1-ORA Corporation) id AA06891; Wed, 23 Dec 92 08:10:15 EST Date: Wed, 23 Dec 92 08:09:35 EST From: shb@com.oracorp Received: by sparta.oracorp.com (4.1/1.3-ORA Corporation) id AA02406; Wed, 23 Dec 92 08:09:35 EST Message-Id: <9212231309.AA02406@sparta.oracorp.com> To: info-hol@edu.uidaho.cs.ted Subject: define_type extension? Is there some profound reason why define_type `foo` `foo = bar1 | bar2 (foo)list`;; gets the response evaluation failed ill-formed type expression(s) ? I can see why expressions defining foo in terms of function types involving foo are sometimes impossible to handle, but there's an obvious recursive algorithm for telling whether an object is an object of type foo. The mut_rec_types contrib entry extends define_type, but I can't test trying to get the same effect with it because its makefile fails at our site for some reason I haven't figured out. Has anyone made an extension of define_type that recognizes lists as exceptionally easy and handles them correctly? Steve Brackin ORA