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/*
* SelectionRule.java
*
* comments here.
*
* @author Michiaki Tatsubori
* @version %VERSION% %DATE%
* @see java.lang.Object
*
* COPYRIGHT 1998 by Michiaki Tatsubori, ALL RIGHTS RESERVED.
*/
package io.devnulllabs.openjava.syntax;
import io.devnulllabs.openjava.ptree.ParseTree;
/**
* The class <code>SelectionRule</code> represents selective syntax
* rule.
* <p>
* Suppose there're several syntax rules; A, B, C. This class
* can represents the syntax ( A | B | C ).
* If both A and B are adaptable to token source, A is choosed since
* A is specified at lefter part than B's part.
*
* @author Michiaki Tatsubori
* @version 1.0
* @since $Id: SelectionRule.java,v 1.2 2003/02/19 02:54:31 tatsubori Exp $
* @see java.lang.Object
*/
public class SelectionRule extends AbstractSyntaxRule {
protected SyntaxRule[] elementRules;
/**
* Allocates a new rule representing a selection of given rules.
*
* @param elementRules an array of rules
*/
public SelectionRule(SyntaxRule[] elementRules) {
this.elementRules = elementRules;
}
public SelectionRule(SyntaxRule e1, SyntaxRule e2) {
this(new SyntaxRule[] { e1, e2 });
}
public SelectionRule(SyntaxRule e1, SyntaxRule e2, SyntaxRule e3) {
this(new SyntaxRule[] { e1, e2, e3 });
}
public ParseTree consume(TokenSource token_src) throws SyntaxException {
for (int i = 0; i < elementRules.length; ++i) {
if (elementRules[i].lookahead(token_src)) {
ParseTree result = elementRules[i].consume(token_src);
return result;
}
}
/***** to become specifed error report */
throw new SyntaxException("neither of selection");
}
}
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