In Designer Studio, Select the PRPC 7 Help System. In the search field, type "Functions". Scroll down until you find the link for "Atlas — Standard Function rules".
PRPC contains more than 400 standard functions you can call, defined through the Function rule form.
Use a function rule to define a Java function that is accessed through rule resolution. You can reference function rules in expressions and directly in Java. Each function belongs to a library (Rule-Utility-Library rule type), indicated by the first key part.
Use the Records Explorer (Technical Category->Functions) to see a complete list of the standard and custom functions available to you.