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Version: 6.x

OVERRIDE operator

The OVERRIDE operator creates a property that implements the selection of one of the values (polymorphic form).


OVERRIDE expr1, ..., exprN


The OVERRIDE operator creates a property whose value will be the value of one of the properties specified in the operator. Selection is made among properties with a non-NULL value. If multiple properties are non-NULL, the value of the first of these properties is selected.


  • expr1, ..., exprN

    List of expressions whose values will determine the value of the property.


CLASS Group;
markup = DATA NUMERIC[8,2] (Group);

markup = DATA NUMERIC[8,2] (Book);
group = DATA Group (Book);
overMarkup (Book b) = OVERRIDE markup(b), markup(group(b));

notNullDate (INTEGER i) = OVERRIDE date(i), 2010_01_01;