org.deri.iris.api.basics
Interface IRule

All Known Implementing Classes:

Rule

public interface IRule

Represents a rule in the program. A rule has a form:

q :- p1, p2,...,pn

where q is a positive literal (the head), and p1, p2,...,pn is a conjunction of several literals (the body). Only safe rules are supported. A rule is safe if its every variable occurs in one of its positive, non built-in, atoms of the body.

$Id: IRule.java,v 1.9 2007-10-30 08:28:27 poettler_ric Exp $

Version:

$Revision: 1.9 $

Author:

Darko Anicic, DERI Innsbruck

Method Summary

List<ILiteral>	getBody() Get the rule body.
List<ILiteral>	getHead() Get the rule head-
boolean	isRectified() A rule is rectified if its head has the same form as heads of the other rules from the program, e.g.

Method Detail

getHead

List<ILiteral> getHead()

Get the rule head-

Returns:

The rule head.

getBody

List<ILiteral> getBody()

Get the rule body.

Returns:

The rule body.

isRectified

boolean isRectified()

A rule is rectified if its head has the same form as heads of the other rules from the program, e.g. p(X1,...,Xk) for variables X1,...,Xk.

For a given pair of rules:

• p(a, X, Y) :- r(X, Y)
• p(X, Y, X) :- r(Y, X)

after the rectification we get the following rules:

• p(U, V, W) :- r(V, W), U='a'.
• p(U, V, W) :- r(V, U), W=U.

where both rules have heads of the same form.

Returns:

True if the rule is rectified; otherwise false.