Answer Sources: from Fluents to Interactors

[ NOTE: Meanwhile this has evolved into an open project available here:
https://github.com/jp-diegidio/Nan.System.Sources-Prolog ]

This is a follow-up to my previous post "Answer Sources in Prolog (SWI) - Preview" [1]. Here I present the flow diagram for the worker loop with support for the return operation. Implementation of the return operation upgrades our answer sources from fluents [2] to interactors [3].

(Click the image to open full size.)

(Click the image to open full size.)

[1] My post, "Answer Sources in Prolog (SWI) - Preview":
http://seprogrammo.blogspot.co.uk/2015/09/answer-sources-in-prolog-swi-preview.html

[2] Paul Tarau, "Fluents: A Refactoring of Prolog for Uniform Reflection and Interoperation with External Objects":
http://www.cse.unt.edu/~tarau/research/LeanProlog/RefactoringPrologWithFluents.pdf

[3] Paul Tarau and Arun Majumdar, "Interoperating Logic Engines":
http://www.cse.unt.edu/~tarau/research/LeanProlog/InteroperatingLogicEngines.pdf