ISSUE-76: Equality in Core?

Equality in Core?

State:

CLOSED

Product:

Core

Raised by:

Jos de Bruijn

Opened on:

2008-09-02

Description:

There is already a widespread consensus that Core will not allow equality in the rule heads.

The question which remains: Will Core allow equality in the rule bodies?
It is known that introducing equality in rule bodies does not increase expressiveness: rules with equality in the body can be straightforwardly equivalently (i.e., they have the same models) rewritten to rules without equality. So, equality in the body is simply a syntactic shortcut.

It is argued in [1] that a restricted form of equality should be allowed in the rule bodies to facilitate external function calls. However, as mentioned above, this equality is not necessary. It is simply a syntactic shortcut.


So, we basically have three choices:
a) allow equality in rule bodies
b) allow only a restricted form of equality in rule bodies, as argued in [1]
c) not allow equality in rule bodies


To me personally, (b) does not make sense. Why allow equation of variables and functions, but not variables and variables?
So, I argue that we should either (a) allow or (c) disallow equality in rule bodies.


[1] http://www.w3.org/2005/rules/wiki/Core#Intersection_of_RIF-PRD_and_RIF-BLD

Related Actions Items:

No related actions

Related emails:

1. [ADMIN] Minutes of 23 September 2008 RIF Telecon (from leora@us.ibm.com on 2008-09-29)
2. [Admin] Agenda for RIF telecon 23 Sept (from csma@ilog.fr on 2008-09-22)
3. Re: ISSUE-76: Equality in Core? [Core] (from der@hplb.hpl.hp.com on 2008-09-14)
4. Re: ISSUE-76: Equality in Core? [Core] (from kifer@cs.sunysb.edu on 2008-09-02)
5. ISSUE-76: Equality in Core? [Core] (from sysbot+tracker@w3.org on 2008-09-02)

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