Answer Sources: from Fluents to Interactors

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

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

(click 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