https://github.com/sgrodriguez/ddt a decision tree lib in golang for building custom rules decision tree. It allows adding a pre-processing stage to the input before comparing it with the following possible branches of the tree. One of the default preprocessing stages in ddt is calling a method of a struct (CallStructMethod) and getting the attribute of a struct (GetStructAttribute) using reflection, so you can have a struct user with some methods and attributes and build a tree asking question about the user. Create the tree programmatically or by json.