Library rules

A library rule is a container for a set of related function rules (the Rule-Utility-Function rule type). Create a library rule to hold custom functions for your application, which can supplant and extend standard functions.

The following tabs are available on this form:

  • Check-out and Restore operations are not available for library rules, even for rulesets with the Use check-out? check box selected.
  • Library rules are always available. You cannot change the availability of a library rule to No/Draft Mode, Blocked, Withdrawn, or Final. (However, you can change the availability of functions in the library, and then recompile the library.)

Where referenced

A library rule is the first key part of a function rule. Each reference to a function rule (a call or invocation) identifies the library to which the function rule belongs. You can reference function rules in expressions and in Java code. Expressions are widely used in many rule types to compute property values.

Your system contains several standard libraries and hundreds of standard functions. For example, the standard library rule DateTime (in the Pega-RULES ruleset) contains several standard functions for date and time format conversions.


Use the Records Explorer to list all library rules in your system.


Library rules belong to the Technical category. A library rule is an instance of the Rule-Utility-Library rule type.