Package org.projog.core.predicate.builtin.list

Class Fold

java.lang.Object

org.projog.core.predicate.AbstractPredicateFactory

org.projog.core.predicate.builtin.list.Fold

All Implemented Interfaces:

KnowledgeBaseConsumer, PredicateFactory, PreprocessablePredicateFactory

public final class Fold
extends AbstractPredicateFactory
implements PreprocessablePredicateFactory

foldl(PredicateName, Values, Start, Result) - combines elements of a list into a single term.

See Wikipedia.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	Fold.OptimisedFold
private static class	Fold.Retryable

Field Summary

Fields

Modifier and Type	Field	Description
private static int	FIRST_ARG_ARITY	The arity of the predicate represented by the first argument.

Constructor Summary

Constructors

Constructor	Description
Fold()

Method Summary

Modifier and Type	Method	Description
private static boolean	evaluateFold(PredicateFactory pf, Term action, java.util.List<Term> values, Term start, Term result)
private static Predicate	getFoldPredicate(PredicateFactory pf, Term action, Term values, Term start, Term result)
protected Predicate	getPredicate(Term atom, Term values, Term start, Term result)
PredicateFactory	preprocess(Term arg)
private static java.util.List<Term>	toList(Term values)

Methods inherited from class org.projog.core.predicate.AbstractPredicateFactory

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.projog.core.predicate.PredicateFactory

getPredicate, isAlwaysCutOnBacktrack, isRetryable

Field Detail

FIRST_ARG_ARITY

private static final int FIRST_ARG_ARITY

The arity of the predicate represented by the first argument.

See Also:

Constant Field Values

Constructor Detail

Fold

public Fold()

Method Detail

preprocess

public PredicateFactory preprocess(Term arg)

Specified by:

preprocess in interface PreprocessablePredicateFactory

getPredicate

protected Predicate getPredicate(Term atom,
                                 Term values,
                                 Term start,
                                 Term result)

Overrides:

getPredicate in class AbstractPredicateFactory

getFoldPredicate

private static Predicate getFoldPredicate(PredicateFactory pf,
                                          Term action,
                                          Term values,
                                          Term start,
                                          Term result)

toList

private static java.util.List<Term> toList(Term values)

evaluateFold

private static boolean evaluateFold(PredicateFactory pf,
                                    Term action,
                                    java.util.List<Term> values,
                                    Term start,
                                    Term result)