Class IfThen

java.lang.Object

org.projog.core.predicate.AbstractPredicateFactory

org.projog.core.predicate.builtin.compound.IfThen

All Implemented Interfaces:

KnowledgeBaseConsumer, PredicateFactory, PreprocessablePredicateFactory

public final class IfThen
extends AbstractPredicateFactory
implements PreprocessablePredicateFactory

X->Y - if X succeeds then Y is evaluated.

Note: The behaviour of this predicate changes when it is specified as the first argument of a structure of the form ;/2, i.e. the "disjunction" predicate. When a ->/2 predicate is the first argument of a ;/2 predicate then the resulting behaviour is a "if/then/else" statement of the form ((if->then);else).

See Also:

• Disjunction

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	IfThen.OptimisedIfThen

Constructor Summary

Constructors

Constructor	Description
IfThen()

Method Summary

Modifier and Type	Method	Description
protected Predicate	getPredicate(Term conditionTerm, Term thenTerm)
PredicateFactory	preprocess(Term term)

Methods inherited from class AbstractPredicateFactory

getArithmeticOperators, getFileHandles, getKnowledgeBase, getOperands, getPredicate, getPredicate, getPredicate, getPredicate, getPredicate, getPredicates, getProjogListeners, getSpyPoints, getTermFormatter, init, isRetryable, setKnowledgeBase

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface PredicateFactory

getPredicate, isAlwaysCutOnBacktrack, isRetryable

Constructor Details

IfThen

public IfThen()

Method Details

getPredicate

protected Predicate getPredicate(Term conditionTerm,
 Term thenTerm)

Overrides:

getPredicate in class AbstractPredicateFactory

preprocess

public PredicateFactory preprocess(Term term)

Specified by:

preprocess in interface PreprocessablePredicateFactory