Return-Path: Delivery-Date: Received: from ted.cs.uidaho.edu (no rfc931) by swan.cl.cam.ac.uk with SMTP (PP-6.4); Fri, 15 Jan 1993 11:05:59 +0000 Received: by ted.cs.uidaho.edu (16.6/1.34) id AA01188; Fri, 15 Jan 93 02:02:28 -0800 Sender: info-hol-request@edu.uidaho.cs.ted Errors-To: info-hol-request@edu.uidaho.cs.ted Precedence: bulk Received: from ganymede.inmos.co.uk by ted.cs.uidaho.edu (16.6/1.34) id AA01183; Fri, 15 Jan 93 02:02:16 -0800 Received: from frogland.inmos.co.uk by ganymede.inmos.co.uk; Fri, 15 Jan 93 10:01:39 GMT From: David Shepherd Message-Id: <6361.9301151002@frogland.inmos.co.uk> Subject: Re: new_recursive_definition limitation? To: info-hol@edu.uidaho.cs.ted (info-hol mailing list) Date: Fri, 15 Jan 1993 10:02:02 +0000 (GMT) In-Reply-To: <9301142251.AA07795@sparta.oracorp.com> from "shb@oracorp.com" at Jan 14, 93 05:51:04 pm X-Mailer: ELM [version 2.4 PL20] Content-Type: text Content-Length: 1345 shb@oracorp.com has said: > new_constant(`f`,":num->num");; > new_recursive_definition false foo `test2` > "(test2 f bar0 = 1) /\ > (test2 f (bar1 f1 f2) = (test2 f f1) + (test2 f f2))";; the problem is that you've declared f to be a constant. It gets parsed as a constant in the definition term above, but the recursive definition functions assume that an paramaters to "test2" other than the constructed element of the recursive type are variables (or pehaps pairs of variables). I think what is happening is that something in the internals depends on this and the presence of the constant causes the error - the error message is perhaps a bit of a sweeping statement and doesn't really tell you what the problem is. In any case the presence of "f" in the parameters to "test2" is wrong - try using another variable name instead. Also, why are you declaring "f" as a constant. If you are only doing this so that the type checker knows its type then what you want is set_sticky_type which sets a `default` type for a variable. -------------------------------------------------------------------------- david shepherd: des@inmos.co.uk tel: 0454-616616 x 625 inmos ltd, 1000 aztec west, almondsbury, bristol, bs12 4sq New Year Resolution for 1993: Start using capital letters.