java_cup.shift_action Maven / Gradle / Ivy
package java_cup;
/** This class represents a shift action within the parse table.
* The action simply stores the state that it shifts to and responds
* to queries about its type.
*
* @version last updated: 11/25/95
* @author Scott Hudson
*/
public class shift_action extends parse_action {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Simple constructor.
* @param shft_to the state that this action shifts to.
*/
public shift_action(lalr_state shft_to) throws internal_error
{
/* sanity check */
if (shft_to == null)
throw new internal_error(
"Attempt to create a shift_action to a null state");
_shift_to = shft_to;
}
/*-----------------------------------------------------------*/
/*--- (Access to) Instance Variables ------------------------*/
/*-----------------------------------------------------------*/
/** The state we shift to. */
protected lalr_state _shift_to;
/** The state we shift to. */
public lalr_state shift_to() {return _shift_to;}
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Quick access to type of action. */
public int kind() {return SHIFT;}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Equality test. */
public boolean equals(shift_action other)
{
return other != null && other.shift_to() == shift_to();
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Generic equality test. */
public boolean equals(Object other)
{
if (other instanceof shift_action)
return equals((shift_action)other);
else
return false;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Compute a hash code. */
public int hashCode()
{
/* use the hash code of the state we are shifting to */
return shift_to().hashCode();
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to a string. */
public String toString() {return "SHIFT(to state " + shift_to().index() + ")";}
/*-----------------------------------------------------------*/
}