A natural extension to the Automatic Programming Server, which makes individual specialized components, is to make whole programs by connecting components.
Graphical Programming System (GPS) allows composition of programs involving iteration, accumulators, and data structures. The goal is to produce programs similar to those written by humans.
Producing a program from generic components requires many view types with complex property definitions. A key feature of GPS is propagation and inference of types and properties to reduce the amount of user input and assist the user in making choices.