/*
* STANDARD ML OF NEW JERSEY COPYRIGHT NOTICE, LICENSE AND DISCLAIMER.
*
* Copyright (c) 1989-1998 by Lucent Technologies
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted, provided
* that the above copyright notice appear in all copies and that both the
* copyright notice and this permission notice and warranty disclaimer appear
* in supporting documentation, and that the name of Lucent Technologies, Bell
* Labs or any Lucent entity not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior permission.
*
* Lucent disclaims all warranties with regard to this software, including all
* implied warranties of merchantability and fitness. In no event shall Lucent
* be liable for any special, indirect or consequential damages or any damages
* whatsoever resulting from loss of use, data or profits, whether in an action
* of contract, negligence or other tortious action, arising out of or in
* connection with the use or performance of this software.
*
* Taken from this URL:
* http://www.smlnj.org/license.html
*
* This license is compatible with the GNU GPL (see section "Standard ML of New
* Jersey Copyright License"):
* http://www.gnu.org/licenses/license-list.html#StandardMLofNJ
*/
/*
* Copyright 1996-1999 by Scott Hudson, Frank Flannery, C. Scott Ananian
*/
package weka.core.parser.java_cup;
/** 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 weka.core.parser.java_cup.terminal
* @see weka.core.parser.java_cup.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();
}
/*-----------------------------------------------------------*/
}