GrammarElement.java

/*******************************************************************************
 * Copyright (c) 2008 Scott Stanchfield.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Based on the ANTLR parser generator by Terence Parr, http://antlr.org
 *   Ric Klaren <klaren@cs.utwente.nl>
 *   Scott Stanchfield - Modifications for XML Parsing
 *******************************************************************************/
package com.javadude.antxr;

/**A GrammarElement is a generic node in our
 * data structure that holds a grammar in memory.
 * This data structure can be used for static
 * analysis or for dynamic analysis (during parsing).
 * Every node must know which grammar owns it, how
 * to generate code, and how to do analysis.
 */
abstract class GrammarElement {
    public static final int AUTO_GEN_NONE = 1;
    public static final int AUTO_GEN_CARET = 2;
    public static final int AUTO_GEN_BANG = 3;

    /*
	 * Note that Java does static argument type matching to
	 * determine which function to execute on the receiver.
	 * Here, that implies that we cannot simply say
	 * grammar.generator.gen(this) in GrammarElement or
	 * only CodeGenerator.gen(GrammarElement ge) would
	 * ever be called.
	 */
    protected Grammar grammar;
    protected int line;
    protected int column;

    public GrammarElement(Grammar g) {
        grammar = g;
        line = -1;
        column = -1;
    }

    public GrammarElement(Grammar g, Token start) {
        grammar = g;
        line = start.getLine();
        column = start.getColumn();
    }

    public void generate() {
		// nothing
    }

    public int getLine() {
        return line;
    }

    public int getColumn() {
        return column;
    }

    public Lookahead look(int k) {
        return null;
    }

    @Override
    public abstract String toString();
}