[Fwd: Re: Uniqueness in a set of variables]

-------- Original Message --------
Subject: Re: [eclipse-users] Uniqueness in a set of variables
Date: Fri, 05 Oct 2001 10:31:04 +0100
From: Joachim Schimpf <j.schimpf@icparc.ic.ac.uk>
Organization: IC-Parc, Imperial College, London
To: Loizos Michael <gemichael@cytanet.com.cy>,eclipse_bugs@icparc.ic.ac.uk
References:
<200110021829.f92IT4n06146@demokritos.cytanet.com.cy><Version.32.20011003233554.00df86e0@mail.cytanet.com.cy>
<200110041728.f94HSZb31437@demokritos.cytanet.com.cy>

Loizos Michael wrote:
> 
> Hello,
> 
> >> and in case there are, the resulting list depends on
> >> the order of the terms on the initial list.
> >
> >But this seems to be ok. If
> >prune_instances([f(X),f(a)], L)  gives  [f(X)]
> >then it seems to be reasonable that
> >prune_instances([f(X),f(Y)], L)  gives  [f(X)]
> >It could alternatively give [f(Y)] or [f(_)], but you
> >probably don't care about the identity of the variable.
> 
> Yes, but:
> ?- prune_instances([f(1, Z), f(Q, 2), f(X, Y)], List).
> Z = Z
> Q = Q
> X = X
> Y = Y
> List = [f(X, Y), f(Q, 2)]
> Yes (0.00s cpu)
> 
> which is wrong.


You're right, we'll register it as a bug.

Thanks,
-- 
 Joachim Schimpf              /             phone: +44 20 7594 8187
 IC-Parc, Imperial College   /            mailto:J.Schimpf@ic.ac.uk
 London SW7 2AZ, UK         /    http://www.icparc.ic.ac.uk/eclipse