/*
* 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 class represents a transition in an LALR viable prefix recognition
* machine. Transitions can be under terminals for non-terminals. They are
* internally linked together into singly linked lists containing all the
* transitions out of a single state via the _next field.
*
* @see weka.core.parser.java_cup.lalr_state
* @version last updated: 11/25/95
* @author Scott Hudson
*
*/
public class lalr_transition {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Full constructor.
* @param on_sym symbol we are transitioning on.
* @param to_st state we transition to.
* @param nxt next transition in linked list.
*/
public lalr_transition(symbol on_sym, lalr_state to_st, lalr_transition nxt)
throws internal_error
{
/* sanity checks */
if (on_sym == null)
throw new internal_error("Attempt to create transition on null symbol");
if (to_st == null)
throw new internal_error("Attempt to create transition to null state");
/* initialize */
_on_symbol = on_sym;
_to_state = to_st;
_next = nxt;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constructor with null next.
* @param on_sym symbol we are transitioning on.
* @param to_st state we transition to.
*/
public lalr_transition(symbol on_sym, lalr_state to_st) throws internal_error
{
this(on_sym, to_st, null);
}
/*-----------------------------------------------------------*/
/*--- (Access to) Instance Variables ------------------------*/
/*-----------------------------------------------------------*/
/** The symbol we make the transition on. */
protected symbol _on_symbol;
/** The symbol we make the transition on. */
public symbol on_symbol() {return _on_symbol;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** The state we transition to. */
protected lalr_state _to_state;
/** The state we transition to. */
public lalr_state to_state() {return _to_state;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Next transition in linked list of transitions out of a state */
protected lalr_transition _next;
/** Next transition in linked list of transitions out of a state */
public lalr_transition next() {return _next;}
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Convert to a string. */
public String toString()
{
String result;
result = "transition on " + on_symbol().name() + " to state [";
result += _to_state.index();
result += "]";
return result;
}
/*-----------------------------------------------------------*/
}