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