public Object getValue(ActionContext ac)
	throws XelException {
		if (_expr == null)
			if (_value != null && _value.indexOf("${") >= 0)
				_expr = ac.parseExpression(_value, _expected);
			else
				_expr = Expressions.DUMMY_EXPRESSION; //to denote not-an-expr
		return _expr == Expressions.DUMMY_EXPRESSION ? coerce(): ac.evaluate(_expr);
	}