Filter (FILTER)

The filter operator creates a property that returns TRUE if the object collection matches the current filter of the specified object group, and NULL if it does not.

Language

To declare a property that determines matching the filter use the FILTER operator.

Examples

CLASS Store;
name = DATA STRING[100] (Store);

FORM stores
    OBJECTS s = Store
;
countF 'Number of filtered warehouses' = GROUP SUM 1 IF [ VIEW stores.s](Store s);
orderF 'Order in an object group' (Store s) = PARTITION SUM 1 IF [ FILTER stores.s](s) ORDER [ ORDER stores.s](s), s;
setNameX 'Add X to name'()  {
    LOCAL k = INTEGER ();
    k() <- 0;
    FOR [ FILTER stores.s](Store s) ORDER [ ORDER stores.s](s) DO {
        k() <- k() + 1;
        name(s) <- 'X' + k() + name(s);
    }
}