Filters

As was mentioned earlier, it's possible to follow a backlink by using the .< instead of .. When doing that it's also necessary to specify the type of the object at the start using [is SomeType] if you want to access any of the links or properties. This can be used in a filter as well. For example, to get all movies from Alice's watchlist, try:

A plain English equivalent of the above query would be:

"Show all Movie objects and their titles that Account objects link to via their watchlist link if the Account object's username property is 'Alice'"

The filter expression must evaluate to some boolean value or a set of boolean values for each element of the filtered set. If it evaluates to a set of booleans all objects that have at least one true value in their filter expression set will be included. This is why filtering movies by matching the name of one of the actors can be done like this:

...or like this:

You can use more complex expressions to filter the results. The only condition is that it should be possible to evaluate these expressions for each element (typically an object) of the filtered set. Try the following query for selecting movies that have titles starting with "The" or star Scarlett Johansson: