Class GetChar

java.lang.Object

org.projog.core.predicate.AbstractSingleResultPredicate

org.projog.core.predicate.builtin.io.GetChar

All Implemented Interfaces:

KnowledgeBaseConsumer, PredicateFactory

public final class GetChar
extends AbstractSingleResultPredicate

get_char(X) - reads the next character from the input stream.

The goal succeeds if X can be unified with next character read from the current input stream. Succeeds only once and the operation of moving to the next character is not undone on backtracking.

If there are no more characters to read from the current input stream (i.e. if the end of the stream has been reached) then an attempt is made to unify X with an atom with the value end_of_file.

Constructor Summary

Constructors

Constructor	Description
GetChar()

Method Summary

Modifier and Type	Method	Description
protected boolean	evaluate(Term argument)

Methods inherited from class AbstractSingleResultPredicate

evaluate, evaluate, evaluate, evaluate, getArithmeticOperators, getFileHandles, getKnowledgeBase, getOperands, 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

isAlwaysCutOnBacktrack, preprocess

Constructor Details

GetChar

public GetChar()

Method Details

evaluate

protected boolean evaluate(Term argument)

Overrides:

evaluate in class AbstractSingleResultPredicate