Functions tab of the Rule Wizard

A function is a reusable piece of code that extends the behavior of a rule. A function provides part or all of a rule expression. Without functions, a rule can support simple expressions with no control-flow statements or compound statements. Functions make possible or greatly simplify complex calculations or decision-making functionality in rule expressions. Functions are global. They do not have a scope and can be used in any rule created in a study or library as long as they are part of the study or library.

Functions allow users with different levels of programming experience to participate in rule-building:

Experienced programmers with the ability to program in a .NET language (for example, C#) and create .NET assemblies build complex function code outside of the Central Designer application and import it into libraries or studies.
Users who are not familiar with programming languages can create rules or rule templates that use functions.

The Central Designer application includes predefined functions (for example, several functions handle checking the components of date time fields).

You can use functions in a library or study:

In a library—User-defined functions that you imported into a library are available after you publish them. You can use a function in a library when:
- You are working in the library.
- You are working in a study for which the library appears in the Library List.
Note: If you are working in a study, you can use predefined functions that were created in the System Library when the System Library appears in the Library List.
In a study—You can use user-defined functions that you imported into a study.