/**
* Compares two terms in <em>Prolog standard order of terms</em>.<br>
* It is noted that <code>t1.compareTo(t2) == 0</code> has the same <code>boolean</code> value as
* <code>t1.equals(t2)</code>.
*
* @param anotherTerm the term to compared with. It must be dereferenced.
* @return the value <code>0</code> if two terms are identical; a value less than <code>0</code>
* if this term is <em>before</em> the <code>anotherTerm</code>; and a value greater than
* <code>0</code> if this term is <em>after</em> the <code>anotherTerm</code>.
*/
public int compareTo(Term anotherTerm) { // anotherTerm must be dereferenced.
if (anotherTerm.isVariable() || anotherTerm.isNumber()) return AFTER;
if (!anotherTerm.isSymbol()) return BEFORE;
if (this == anotherTerm) return EQUAL;
int x = name.compareTo(((SymbolTerm) anotherTerm).name());
if (x != 0) return x;
int y = this.arity - ((SymbolTerm) anotherTerm).arity();
if (y != 0) return y;
throw new InternalException("SymbolTerm is not unique");
}
