protected void consumeEqualityExpression(int op) {
	// EqualityExpression ::= EqualityExpression '==' RelationalExpression
	// EqualityExpression ::= EqualityExpression '!=' RelationalExpression

	//optimize the push/pop

	this.expressionPtr--;
	this.expressionLengthPtr--;
	this.expressionStack[this.expressionPtr] =
		new EqualExpression(
			this.expressionStack[this.expressionPtr],
			this.expressionStack[this.expressionPtr + 1],
			op);
}