java_cup-0.11a.src.java_cup.production_part Maven / Gradle / Ivy
package java_cup;
/** This class represents one part (either a symbol or an action) of a
* production. In this base class it contains only an optional label
* string that the user can use to refer to the part within actions.
*
* This is an abstract class.
*
* @see java_cup.production
* @version last updated: 11/25/95
* @author Scott Hudson
*/
public abstract class production_part {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Simple constructor. */
public production_part(String lab)
{
_label = lab;
}
/*-----------------------------------------------------------*/
/*--- (Access to) Instance Variables ------------------------*/
/*-----------------------------------------------------------*/
/** Optional label for referring to the part within an action (null for
* no label).
*/
protected String _label;
/** Optional label for referring to the part within an action (null for
* no label).
*/
public String label() {return _label;}
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Indicate if this is an action (rather than a symbol). Here in the
* base class, we don't this know yet, so its an abstract method.
*/
public abstract boolean is_action();
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Equality comparison. */
public boolean equals(production_part other)
{
if (other == null) return false;
/* compare the labels */
if (label() != null)
return label().equals(other.label());
else
return other.label() == null;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Generic equality comparison. */
public boolean equals(Object other)
{
if (!(other instanceof production_part))
return false;
else
return equals((production_part)other);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Produce a hash code. */
public int hashCode()
{
return label()==null ? 0 : label().hashCode();
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to a string. */
public String toString()
{
if (label() != null)
return label() + ":";
else
return " ";
}
/*-----------------------------------------------------------*/
}