llkparser.java

linux下建立JAVA虚拟机的源码KAFFE

package antlr;

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.cs.usfca.edu
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id: LLkParser.java,v 1.2 2005/12/24 21:50:48 robilad Exp $
 */

import java.io.IOException;

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

    public LLkParser(int k_) {
        k = k_;
    }

    public LLkParser(ParserSharedInputState state, int k_) {
        super(state);
		k = k_;
    }

    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() throws TokenStreamException {
        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(", ");
            }
            if ( LT(i)!=null ) {
                System.out.print("LA(" + i + ")==" + LT(i).getText());
            }
            else {
                System.out.print("LA(" + i + ")==null");
            }
        }
        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;
    }
}