Custom functions may also be referenced by expressions defined in an IEG script. For example:
<loop loop-type="for-each" entity="Person" criteria="isNotNull(Person.hasIncome) and hasIncome==true)">
As custom functions are a server side phenomenon they may not be referenced by expressions that are evaluated on the client side. This means that custom functions may not be referenced by expressions of dynamically conditional clusters. Please also note that custom functions cannot accept a variable number of parameters. See the Cúram Rules Codification Guide for more information on defining and implementing custom functions.