blockcontext.java

来自「SRI international 发布的OAA框架软件」· Java 代码 · 共 31 行

package antlr_oaa;

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/RIGHTS.html
 *
 * $Id: BlockContext.java,v 1.1 2002/11/08 17:38:20 agno Exp $
 */

/**BlockContext stores the information needed when creating an
 * alternative (list of elements).  Entering a subrule requires
 * that we save this state as each block of alternatives
 * requires state such as "tail of current alternative."
 */
class BlockContext {
	AlternativeBlock block; // current block of alternatives
	int altNum;				// which alt are we accepting 0..n-1
	BlockEndElement blockEnd; // used if nested


	public void addAlternativeElement(AlternativeElement e) {
		currentAlt().addElement(e);
	}
	public Alternative currentAlt() {
		return (Alternative)block.alternatives.elementAt(altNum);
	}
	public AlternativeElement currentElement() {
		return currentAlt().tail;
	}
}