java_cup-0.11a.src.java_cup.parse_action Maven / Gradle / Ivy
Go to download
CUP is a system for generating LALR parsers from simple specifications. It serves the same role as
the widely used program YACC [1] and in fact offers most of the features of YACC. However, CUP is
written in Java, uses specifications including embedded Java code, and produces parsers which are
implemented in Java.
The newest version!
package java_cup;
/** This class serves as the base class for entries in a parse action table.
* Full entries will either be SHIFT(state_num), REDUCE(production), NONASSOC,
* or ERROR. Objects of this base class will default to ERROR, while
* the other three types will be represented by subclasses.
*
* @see java_cup.reduce_action
* @see java_cup.shift_action
* @version last updated: 7/2/96
* @author Frank Flannery
*/
public class parse_action {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Simple constructor. */
public parse_action()
{
/* nothing to do in the base class */
}
/*-----------------------------------------------------------*/
/*--- (Access to) Static (Class) Variables ------------------*/
/*-----------------------------------------------------------*/
/** Constant for action type -- error action. */
public static final int ERROR = 0;
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constant for action type -- shift action. */
public static final int SHIFT = 1;
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constants for action type -- reduce action. */
public static final int REDUCE = 2;
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constants for action type -- reduce action. */
public static final int NONASSOC = 3;
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Quick access to the type -- base class defaults to error. */
public int kind() {return ERROR;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Equality test. */
public boolean equals(parse_action other)
{
/* we match all error actions */
return other != null && other.kind() == ERROR;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Generic equality test. */
public boolean equals(Object other)
{
if (other instanceof parse_action)
return equals((parse_action)other);
else
return false;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Compute a hash code. */
public int hashCode()
{
/* all objects of this class hash together */
return 0xCafe123;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to string. */
public String toString() {return "ERROR";}
/*-----------------------------------------------------------*/
}