Class CharType

java.lang.Object

org.projog.core.predicate.builtin.classify.CharType

All Implemented Interfaces:

PredicateFactory

public final class CharType
extends Object
implements PredicateFactory

char_type(X,Y) - classifies characters.

Succeeds if the character represented by X is a member of the character type represented by Y. Supported character types are:

• digit
• upper - upper case letter
• lower - lower case letter
• alpha - letter (upper or lower)
• alnum - letter (upper or lower) or digit
• white - whitespace

Constructor Summary

Constructors

Constructor	Description
CharType()

Method Summary

Modifier and Type	Method	Description
Predicate	getPredicate(Term input)	Returns a Predicate to be used in the evaluation of a goal.
boolean	isRetryable()	Should instances of this implementation be re-evaluated when backtracking?

Methods inherited from class Object

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

Methods inherited from interface PredicateFactory

isAlwaysCutOnBacktrack, preprocess

Constructor Details

CharType

public CharType()

Method Details

getPredicate

public Predicate getPredicate(Term input)

Description copied from interface: PredicateFactory

Returns a Predicate to be used in the evaluation of a goal.

Specified by:

getPredicate in interface PredicateFactory

Parameters:

input - the term containing the arguments to use in the evaluation of the goal

Returns:

Predicate to be used in the evaluation of the goal

See Also:

• Predicate.evaluate()

isRetryable

public boolean isRetryable()

Description copied from interface: PredicateFactory

Should instances of this implementation be re-evaluated when backtracking?

Some goals (e.g. X is 1) are only meant to be evaluated once (the statement is either true or false) while others (e.g. repeat(3)) are meant to be evaluated multiple times. For instances of Predicate that are designed to possibly have Predicate.evaluate() called on them multiple times for the same individual query this method should return true. For instances of Predicate that are designed to only be evaluated once per individual query this method should return false.

Specified by:

isRetryable in interface PredicateFactory

Returns:

true if an attempt should be made to re-evaluate instances of implementing classes when backtracking, false otherwise