Decipher is a very robust and free flowing platform allowing xml and python access to control survey flow. Here is a primer to help get started. There are many more documents to help get started outside of these.
1: Advanced logic
Logic can be added and referenced in various ways. Below are a few of the advanced options.
Python is the basis for the advanced scripting in Decipher. Many functions have been transferred and pre-coded into survey attributes and included in the standard Decipher library. However, Python can be used to create custom functionality as needed within a survey.
3: Survey Attributes
Many many typical tasks within a survey have been pre-coded into a attribute library, making it easy to create questions and functionality without the need to custom script solutions. Some of these are explained below.
4: Helpful Survey Editor Resources
The survey editor, though an efficient UI, is tied into the back end scripting as well. Through the use of the attributes and XML editor, you can tie in the needed functionality.