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package java_cup;
/** This class represents a part of a production which is a symbol (terminal
* or non terminal). This simply maintains a reference to the symbol in
* question.
*
* @see java_cup.production
* @version last updated: 11/25/95
* @author Scott Hudson
*/
public class symbol_part extends production_part {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Full constructor.
* @param sym the symbol that this part is made up of.
* @param lab an optional label string for the part.
*/
public symbol_part(symbol sym, String lab) throws internal_error
{
super(lab);
if (sym == null)
throw new internal_error(
"Attempt to construct a symbol_part with a null symbol");
_the_symbol = sym;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constructor with no label.
* @param sym the symbol that this part is made up of.
*/
public symbol_part(symbol sym) throws internal_error
{
this(sym,null);
}
/*-----------------------------------------------------------*/
/*--- (Access to) Instance Variables ------------------------*/
/*-----------------------------------------------------------*/
/** The symbol that this part is made up of. */
protected symbol _the_symbol;
/** The symbol that this part is made up of. */
public symbol the_symbol() {return _the_symbol;}
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Respond that we are not an action part. */
public boolean is_action() { return false; }
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Equality comparison. */
public boolean equals(symbol_part other)
{
return other != null && super.equals(other) &&
the_symbol().equals(other.the_symbol());
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Generic equality comparison. */
public boolean equals(Object other)
{
if (!(other instanceof symbol_part))
return false;
else
return equals((symbol_part)other);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Produce a hash code. */
public int hashCode()
{
return super.hashCode() ^
(the_symbol()==null ? 0 : the_symbol().hashCode());
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to a string. */
public String toString()
{
if (the_symbol() != null)
return super.toString() + the_symbol();
else
return super.toString() + "$$MISSING-SYMBOL$$";
}
/*-----------------------------------------------------------*/
};