package java_cup;
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/** This class represents a part of a production which is a symbol (terminal
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* or non terminal). This simply maintains a reference to the symbol in
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* question.
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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 class symbol_part extends production_part {
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/*-----------------------------------------------------------*/
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/*--- Constructor(s) ----------------------------------------*/
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/*-----------------------------------------------------------*/
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/** Full constructor.
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* @param sym the symbol that this part is made up of.
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* @param lab an optional label string for the part.
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*/
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public symbol_part(symbol sym, String lab) throws internal_error
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{
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super(lab);
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if (sym == null)
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throw new internal_error(
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"Attempt to construct a symbol_part with a null symbol");
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_the_symbol = sym;
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}
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/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
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/** Constructor with no label.
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* @param sym the symbol that this part is made up of.
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*/
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public symbol_part(symbol sym) throws internal_error
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{
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this(sym,null);
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}
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/*-----------------------------------------------------------*/
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/*--- (Access to) Instance Variables ------------------------*/
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/*-----------------------------------------------------------*/
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/** The symbol that this part is made up of. */
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protected symbol _the_symbol;
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/** The symbol that this part is made up of. */
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public symbol the_symbol() {return _the_symbol;}
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/*-----------------------------------------------------------*/
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/*--- General Methods ---------------------------------------*/
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/*-----------------------------------------------------------*/
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/** Respond that we are not an action part. */
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public boolean is_action() { return false; }
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/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
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/** Equality comparison. */
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public boolean equals(symbol_part other)
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{
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return other != null && super.equals(other) &&
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the_symbol().equals(other.the_symbol());
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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 symbol_part))
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return false;
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else
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return equals((symbol_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 super.hashCode() ^
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(the_symbol()==null ? 0 : the_symbol().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 (the_symbol() != null)
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return super.toString() + the_symbol();
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else
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return super.toString() + "$$MISSING-SYMBOL$$";
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}
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/*-----------------------------------------------------------*/
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};
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