llkparser.java

SRI international 发布的OAA框架软件

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: LLkParser.java,v 1.1 2002/11/08 17:37:55 agno Exp $
 */

import java.io.IOException;

/**An LL(k) parser.
 *
 * @see antlr_oaa.Token
 * @see antlr_oaa.TokenBuffer
 * @see antlr_oaa.LL1Parser
 */
public class LLkParser extends Parser {
	int k;

	public LLkParser(int k_) {
		k = k_;
		//TokenBuffer tokenBuf = new TokenBuffer(null);
		//setTokenBuffer(tokenBuf);
	}
	public LLkParser(ParserSharedInputState state, int k_) {
		k = k_;
		inputState = state;
	}
	public LLkParser(TokenBuffer tokenBuf, int k_) {
		k = k_;
		setTokenBuffer(tokenBuf);
	}
	public LLkParser(TokenStream lexer, int k_) {
		k = k_;
		TokenBuffer tokenBuf = new TokenBuffer(lexer);
		setTokenBuffer(tokenBuf);
	}
	/**Consume another token from the input stream.  Can only write sequentially!
	 * If you need 3 tokens ahead, you must consume() 3 times.
	 * <p>
	 * Note that it is possible to overwrite tokens that have not been matched.
	 * For example, calling consume() 3 times when k=2, means that the first token
	 * consumed will be overwritten with the 3rd.
	 */
	public void consume() {
		inputState.input.consume();
	}
	public int LA(int i) throws TokenStreamException {
		return inputState.input.LA(i);
	}
	public Token LT(int i) throws TokenStreamException {
		return inputState.input.LT(i);
	}
	private void trace(String ee, String rname) throws TokenStreamException {
		traceIndent();
		System.out.print(ee + rname + ((inputState.guessing>0)?"; [guessing]":"; "));
		for (int i = 1; i <= k; i++)
		{
			if (i != 1) {
				System.out.print(", ");
			}
			System.out.print("LA(" + i + ")==" + LT(i).getText());
		}
		System.out.println("");
	}
	public void traceIn(String rname) throws TokenStreamException {
		traceDepth += 1;
		trace("> ", rname);
	}
	public void traceOut(String rname) throws TokenStreamException {
		trace("< ", rname);
		traceDepth -= 1;
	}
}