programming, when stripped of all its circumstantial irrelevancies,
boils down to no more and no less than very effective thinking so as to avoid unmastered complexity,
to very vigorous separation of your many different concerns.
-- Dijkstra EDW512
https://www.cs.utexas.edu/users/EWD/transcriptions/EWD05xx/EWD512.html
Ruby Conf 12: "Boundaries" - Gary Bernhardt
https://www.youtube.com/watch?v=yTkzNHF6rMs
"Boundaries" - Gary Bernhardt from SCNA 2012
https://www.destroyallsoftware.com/talks/boundaries
Business-Friendly Functional Programming, Part 2: Testability - Yang Bo
http://rea.tech/business-friendly-functional-programming-part-2-testability/
Functional Programming in Swift - slide 55+
http://www.slideshare.net/SaugatGautam2/functional-programming-in-swift
Enemy of the State by Justin Spahr-Summers
https://speakerdeck.com/jspahrsummers/enemy-of-the-state
"Functional core & Imperative shell" : OO design, and isolated tests without mocks
http://blogs.perl.org/users/mascip/2014/06/functional-core-imperative-shell-oo-design-and-isolated-tests-without-mocks.html
http://blogs.perl.org/users/mascip/2014/06/functional-core-imperative-shell-explanation-with-code.html
mokacoding - unit and acceptance testing, automation, productivity
http://www.mokacoding.com/blog/functional-core-reactive-shell/
Functional Core, Imperative Shell - Sean Hammond
http://www.seanh.cc/posts/functional-core-imperative-shell
Functional Programming in Ruby - Vitor Capela
https://speakerdeck.com/dodecaphonic/functional-programming-in-ruby
Test-Driven Development with Python - Harry Percival
https://books.google.dk/books?id=fTLJAwAAQBAJ&pg=PA403&lpg=PA403&dq=%22functional+core%22+%22imperative+shell%22&source=bl&ots=A4g25w7wWY&sig=x0bu4NZWiXrpzWPziAH7Y78AKgM&hl=en&sa=X&ved=0ahUKEwi0jq3em-zPAhUqG5oKHYNJBIE4ChDoAQhRMAk#v=onepage&q=%22functional%20core%22%20%22imperative%20shell%22&f=false
BoochTek, LLC
http://blog.boochtek.com/category/programming/architecture
Object layer, valuelayer - andy_matuschak https://realm.io/news/andy-matuschak-controlling-complexity/
https://www.destroyallsoftware.com/blog/2014/test-isolation-is-about-avoiding-mocks
To Kill a Mockingtest - Ken Scambler
http://rea.tech/to-kill-a-mockingtest/