Right now, because fields may not exist, users can have an awkward time. For instance, checking for is_alert, you end up having to preface checks with exists(is_alert).
For instance, in one of our use-cases: https://github.com/apache/metron/tree/master/use-cases/geographic_login_outliers we use "is_alert := exists(is_alert) && is_alert", "is_alert := is_alert || (geo_outlier != null && geo_outlier == true)", instead of : "is_alert := is_alert || geo_outlier == true", I suggest that we adopt a convention from javascript whereby we assume a field not existing or being null should act as false in boolean expressions. This will simplify stellar's use and hopefully result in less awkwardness. Thoughts?
