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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can obtain
* a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
* or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
* Sun designates this particular file as subject to the "Classpath" exception
* as provided by Sun in the GPL Version 2 section of the License file that
* accompanied this code. If applicable, add the following below the License
* Header, with the fields enclosed by brackets [] replaced by your own
* identifying information: "Portions Copyrighted [year]
* [name of copyright owner]"
*
* Contributor(s):
*
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.java_cup.internal;
/** This abstract class serves as the base class for grammar symbols (i.e.,
* both terminals and non-terminals). Each symbol has a name string, and
* a string giving the type of object that the symbol will be represented by
* on the runtime parse stack. In addition, each symbol maintains a use count
* in order to detect symbols that are declared but never used, and an index
* number that indicates where it appears in parse tables (index numbers are
* unique within terminals or non terminals, but not across both).
*
* @see com.sun.java_cup.internal.terminal
* @see com.sun.java_cup.internal.non_terminal
* @version last updated: 7/3/96
* @author Frank Flannery
*/
public abstract class symbol {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Full constructor.
* @param nm the name of the symbol.
* @param tp a string with the type name.
*/
public symbol(String nm, String tp)
{
/* sanity check */
if (nm == null) nm = "";
/* apply default if no type given */
if (tp == null) tp = "Object";
_name = nm;
_stack_type = tp;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constructor with default type.
* @param nm the name of the symbol.
*/
public symbol(String nm)
{
this(nm, null);
}
/*-----------------------------------------------------------*/
/*--- (Access to) Instance Variables ------------------------*/
/*-----------------------------------------------------------*/
/** String for the human readable name of the symbol. */
protected String _name;
/** String for the human readable name of the symbol. */
public String name() {return _name;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** String for the type of object used for the symbol on the parse stack. */
protected String _stack_type;
/** String for the type of object used for the symbol on the parse stack. */
public String stack_type() {return _stack_type;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Count of how many times the symbol appears in productions. */
protected int _use_count = 0;
/** Count of how many times the symbol appears in productions. */
public int use_count() {return _use_count;}
/** Increment the use count. */
public void note_use() {_use_count++;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Index of this symbol (terminal or non terminal) in the parse tables.
* Note: indexes are unique among terminals and unique among non terminals,
* however, a terminal may have the same index as a non-terminal, etc.
*/
protected int _index;
/** Index of this symbol (terminal or non terminal) in the parse tables.
* Note: indexes are unique among terminals and unique among non terminals,
* however, a terminal may have the same index as a non-terminal, etc.
*/
public int index() {return _index;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Indicate if this is a non-terminal. Here in the base class we
* don't know, so this is abstract.
*/
public abstract boolean is_non_term();
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to a string. */
public String toString()
{
return name();
}
/*-----------------------------------------------------------*/
}