Outline

Objects need to be processed: queried or transformed.
The concerns the programmer has
at the design level: ClassGraph, WhereToGo, WhatToDo.
WhereToGo depends on ClassGraph and WhatToDo.
WhatToDo depends on ClassGraph and WhereToGo.

Goal: Keep the concerns separated at the implementation level:
Make our programs look like designs.
Better separation of concerns by using a functional approach:
AP-F.

AP-F
Use series-parallel graphs and assume consistency.
Focus on the programming model of DemeterF: 
Programming in flows.

Theory and Implementation of WhereToGo: 
Your traversal graph construction.