From fedc674a40f2f23d3d8bbd9c4ddc3e50d20994a9 Mon Sep 17 00:00:00 2001 From: EuAndreh Date: Sun, 8 Nov 2020 15:49:02 -0300 Subject: Add next paradigm article --- ...t-paradigm-shift-in-programming-video-review.md | 160 +++++++++++++++++++++ 1 file changed, 160 insertions(+) create mode 100644 _articles/2020-11-08-the-next-paradigm-shift-in-programming-video-review.md (limited to '_articles/2020-11-08-the-next-paradigm-shift-in-programming-video-review.md') diff --git a/_articles/2020-11-08-the-next-paradigm-shift-in-programming-video-review.md b/_articles/2020-11-08-the-next-paradigm-shift-in-programming-video-review.md new file mode 100644 index 0000000..ff9be5a --- /dev/null +++ b/_articles/2020-11-08-the-next-paradigm-shift-in-programming-video-review.md @@ -0,0 +1,160 @@ +--- + +title: The Next Paradigm Shift in Programming - video review + +date: 2020-11-08 + +layout: post + +lang: en + +ref: the-next-paradigm-shift-in-programming-video-review + +category: video review + +--- + +This is a review with comments of +"[The Next Paradigm Shift in Programming][video-link]", by Richard Feldman. + +This video was *strongly* suggested to me by a colleague. I wanted to discuss it +with her, and when drafting my response I figured I could publish it publicly +instead. + +Before anything else, let me just be clear: I really like the talk, and I think +Richard is a great public speaker. I've watched several of his talks over the +years, and I feel I've followed his career at a distance, with much respect. +This isn't a piece criticizing him personally, and I agree with almost +everything he said. These are just some comments but also nitpicks on a few +topics I think he missed, or that I view differently. + +[video-link]: https://www.youtube.com/watch?v=6YbK8o9rZfI + +## Structured programming + +The historical overview at the beginning is very good. In fact, the very video I +watched previously was about structured programming! + +Kevlin Henney on +"[The Forgotten Art of Structured Programming][structured-programming]" does a +deep-dive on the topic of structured programming, and how on his view it is +still hidden in our code, when we do a `continue` or a `break` in some ways. +Even though it is less common to see an explicit `goto` in code these days, many +of the original arguments of Dijkstra against explicit `goto`s is applicable to +other constructs, too. + +This is a very mature view, and I like how he goes beyond the +"don't use `goto`s" heuristic and proposes and a much more nuanced understanding +of what "structured programming" means. + +In a few minutes, Richard is able to condense most of the significant bits of +Kevlin's talk in a didactical way. Good job. + +[structured-programming]: https://www.youtube.com/watch?v=SFv8Wm2HdNM + +## OOP like a distributed system + +Richard extrapolates Alan Kay's original vision of OOP, and he concludes that +it is more like a distributed system that how people think about OOP these days. +But he then states that this is a rather bad idea, and we shouldn't pursue it, +given that distributed systems are known to be hard. + +However, his extrapolation isn't really impossible, bad or an absurd. In fact, +it has been followed through by Erlang. Joe Armstrong used to say that +"[Erlang might the only OOP language][erlang-oop]", since it actually adopted +this paradigm. + +But Erlang is a functional language. So this "OOP as a distributed system" view +is more about designing systems in the large than programs in the small. + +There is a switch of levels in this comparison I'm making, as can be done with +any language or paradigm: you can have a functional-like system that is built +with an OOP language (like a compiler, that given the same input will produce +the same output), or an OOP-like system that is built with a functional language +(Rich Hickey calls it +"[OOP in the large][langsys]"[^the-language-of-the-system]). + +So this jump from in-process paradigm to distributed paradigm is rather a big +one, and I don't think you he can argue that OOP has anything to say about +software distribution across nodes. You can still have Erlang actors that run +independently and send messages to each other without a network between them. +Any OTP application deployed on a single node effectively works like that. + +I think he went a bit too far with this extrapolation. Even though I agree it is +a logical a fair one, it isn't evidently bad as he painted. I would be fine +working with a single-node OTP application and seeing someone call it "a *real* +OOP program". + +[erlang-oop]: https://www.infoq.com/interviews/johnson-armstrong-oop/ +[langsys]: https://www.youtube.com/watch?v=ROor6_NGIWU +[^the-language-of-the-system]: From 24:05 to 27:45. + +## First class immutability + +I agree with his view of languages moving towards the functional paradigm. +But I think you can narrow down the "first-class immutability" feature he points +out as present on modern functional programming languages to "first-class +immutable data structures". + +I wouldn't categorize a language as "supporting functional programming style" +without a library for functional data structures it. By discipline you can avoid +side-effects, write pure functions as much as possible, and pass functions as +arguments around is almost every language these days, but if when changing an +element of a vector mutates things in-place, that is still not functional +programming. + +To avoid that, you end-up needing to make clones of objects to pass to a +function, using freezes or other workarounds. All those cases are when the +underlying mix of OOP and functional programming fail. + +There are some languages with third-party libraries that provide functional data +structures, like [immer][immer] for C++, or [ImmutableJS][immutablejs] for +JavaScript. + +But functional programming is more easily achievable in languages that have them +built-in, like Erlang, Elm and Clojure. + +[immer]: https://sinusoid.es/immer/ +[immutablejs]: https://immutable-js.github.io/immutable-js/ + +## Managed side-effects + +His proposal of adopting managed side-effects as a first-class language concept +is really intriguing. + +This is something you can achieve with a library, like [Redux][redux] for JavaScript or +[re-frame][re-frame] for Clojure. + +I haven't worked with a language with managed side-effects at scale, and I don't +feel this is a problem with Clojure or Erlang. But is this me finding a flaw in +his argument or not acknowledging a benefit unknown to me? This is a provocative +question I ask myself. + +Also all FP languages with managed side-effects I know are statically-typed, and +all dynamically-typed FP languages I know don't have managed side-effects baked in. + +[redux]: https://redux.js.org/ +[re-frame]: https://github.com/Day8/re-frame + +## What about declarative programming? + +In "[Out of the Tar Pit][tar-pit]", B. Moseley and P. Marks go beyond his view +of functional programming as the basis, and name a possible "functional +relational programming" as an even better solution. They explicitly call out +some flaws in most of the modern functional programming languages, and instead +pick declarative programming as an even better starting paradigm. + +If the next paradigm shift is towards functional programming, will the following +shift be towards declarative programming? + +[tar-pit]: http://curtclifton.net/papers/MoseleyMarks06a.pdf + +## Conclusion + +Beyond all Richard said, I also hear often bring up functional programming when +talking about utilizing all cores of a computer, and how FP can help with that. + +Rich Hickey makes a great case for single-process FP on his famous talk +"[Simple Made Easy][simple-made-easy]". + +[simple-made-easy]: https://www.infoq.com/presentations/Simple-Made-Easy/ -- cgit v1.2.3